Perspective
䢇
The Hypothesis-Oriented Algorithm
for Clinicians II (HOAC II):
A Guide for Patient Management
ўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўў
In this era of health care accountability, a need exists for a new
decision-making and documentation guide in physical therapy. The
original Hypothesis-Oriented Algorithm for Clinicians (HOAC) provided clinicians and students with a framework for science-based
clinical practice and focused on the remediation of functional deficits
and how changes in impairments related to these deficits. The HOAC
II was designed to address shortcomings in the original HOAC and be
more compatible with contemporary practice, including the Guide to
Physical Therapist Practice. Disablement terminology is used in the
HOAC II to guide clinicians and students when documenting patient
care and incorporating evidence into practice. The HOAC II, like the
HOAC, can be applied to a patient regardless of age or disorder and
allows for identification of problems by physical therapists when
patients are not able to communicate their problems. A feature of the
HOAC II that was lacking in the original algorithm is the concept of
prevention and how to justify and document interventions directed at
prevention. [Rothstein JM, Echternach JL, Riddle DL. The HypothesisOriented Algorithm for Clinicians II (HOAC II): a guide for patient
management. Phys Ther. 2003;83:455– 470.]
Key Words: Decision making; Diagnosis; Physical therapy profession, professional issues.
ўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўўў
Jules M Rothstein, John L Echternach, Daniel L Riddle
Physical Therapy . Volume 83 . Number 5 . May 2003
455
The HOAC II is a revised algorithm
I
n 1986, Rothstein and Echternach1 published a
clinical decision and documentation guide called
the Hypothesis-Oriented Algorithm for Clinicians
(HOAC), which they contended offered clinicians
a pragmatic, scientifically credible approach to patient
management. Since that algorithm was first published,
radical changes have occurred in the health care system.
For example, there is now widespread discussion of the
importance of physical therapists making diagnoses,2
and there is also general acceptance of the need to view
patients and clients within the context of one of the
disability models.3,4 In addition, therapists often have to
relate to practice guides and guidelines.5 We argue that
what is needed is a patient management system that
involves the patient in decision making and can be used
to provide payers with better justifications for interventions, including occasions when therapists may disagree
with practice guidelines. Compatibility with the Guide to
Physical Therapist Practice’s (Guide’s) patient management model, including the formulation of diagnoses, is
also desirable.6
The purpose of this article is to present HOAC II, a
revised algorithm designed to meet the needs of contemporary practice. The algorithm, we believe, is compatible with the American Physical Therapy Association’s
(APTA’s) Guide to Physical Therapist Practice,6 including
the therapists’ need to diagnose and to offer interventions designed to prevent problems. In the context of
the HOAC II, a problem is almost always a functional
deficit. Although we attempted to be consistent with
Guide terms, there are instances where we used alternate
terms for the sake of clarity.
Although the original HOAC was a first effort at bringing scientific decision making into a user-friendly practical context for clinical decision making, it has some
cumbersome elements as well some logical and procedural flaws. The algorithm offered no guidance on how
to determine when an intervention designed primarily
for prevention was appropriate and how risk factors
could be eliminated. The algorithm also did not adequately provide a means for identifying problems and
designed to meet the needs of
contemporary practice.
addressing goals noted by someone other than the
patient.
The focus on patient-centered outcomes was, however,
an innovation in HOAC and laid a foundation for the
implementation of the HOAC in clinical decision making in the context of currently used disability models.
The disablement model that we believe currently offers
the greatest utility for clinical practice is the Nagi
model.7(pp223–241) A common element in both the old
and new versions of the HOAC is that therapists using
the terms of the Nagi model are called upon to identify
impairments, when appropriate; to examine how these
impairments relate to functional deficits; and to examine whether interventions designed to ameliorate or
reduce impairments result in changes in function and
changes in levels of disability. In some cases, therapists
also can hypothesize that factors other than impairments
may lead to functional loss. For example, a societal
limitation such as high curbs may contribute to a
patient’s inability to walk to school. We also believe
therapists have a role in prevention7(pp84 – 89) and that in
a responsibility-focused health care system clinicians
should identify the hypotheses that underlie interventions used for prevention.
We believed that the original HOAC could serve both as
a template for documentation and as a conceptual
model for decision making and, therefore, could link
documentation and practice. This does not mean, however, that we believe either the original HOAC or the
HOAC II must be implemented in the exact form we
have written it, for all patients, in all settings. Rather, we
contend that elements can be selected based on practicality and the expected benefit of using a system in
which all elements of patient management are explicitly
detailed. The HOAC II, we contend, provides a means
for not only using evidence in decision making, but also
for documenting the nature and extent of evidence
used. Within the new version, elements related to justi-
JM Rothstein, PT, PhD, FAPTA, is Professor, Department of Physical Therapy, College of Applied Health Sciences, University of Illinois at Chicago,
1919 W Taylor St, 4th Fl, Room 456, Chicago, IL 60612 (jules-rothstein@attbi.com). Address all correspondence to Dr Rothstein.
JL Echternach, PT, EdD, ECS, FAPTA, is Professor and Eminent Scholar, School of Physical Therapy, Old Dominion University, Norfolk, Va.
DL Riddle, PT, PhD, is Professor, Department of Physical Therapy, Medical College of Virginia Campus, Virginia Commonwealth University,
Richmond, Va.
All authors provided concept/idea/project design, writing, and project management. The authors acknowledge the efforts of Andrew Guccione,
PT, PhD, FAPTA, Julie Fritz, PT, PhD, ATC, and David Scalzitti, PT, MS, OCS, for reviewing an earlier draft of the manuscript.
This article was submitted March 12, 2002, and was accepted December 2, 2002.
456 . Rothstein et al
Physical Therapy . Volume 83 . Number 5 . May 2003
ўўўўўўўўўўўўўўўўўўўўўўўўўўў
fication of interventions (eg, where evidence can be
cited) should be part of any credible system of
documentation.
Overview of Elements in HOAC II
In developing the revised algorithm, we recognized that
there are usually 2 major types of patient problems:
(1) those that exist when the patient is being seen and
that require remediation and (2) those that may occur in
the future and that require prevention. We also realized
that even though clinicians do not necessarily routinely
discuss these differences, clinical management of the 2
types of problems is different, and assessment of the
outcomes for each must differ.
While there are 2 types of problems (existing and
anticipated), there are also 2 ways that problems are
identified. There are patient-identified problems (PIPs)
and non–patient-identified problems (NPIPs). Patientidentified problems, which usually consist of functional
limitations and disabilities, often exist when the therapist sees the patient. The patient identifies the problem.
The therapist, however, needs to generate hypotheses as
to the cause of problems and to establish testing criteria,
which can be used to evaluate the outcomes of interventions, and the correctness of the hypothesis and patient
care strategies. The patient may identify existing problems as well as express concerns relating to problems
that do not yet exist and could, therefore, be the source
of an anticipated problem. For example, a patient may
complain of shoulder pain and express a concern about
the development of limitations in movements that could
be disabling. The limitations in function caused by the
pain would be an existing problem (eg, an inability to
cook a meal because repetitive use of the shoulder
caused intolerable pain). Any loss of function that could
occur if motion became even more limited would be an
anticipated problem.
Non–patient-identified problems are problems that are
not identified by the patient. They are problems that
may occur as well as existing problems. For example,
children may not be able to identify problems secondary
to central nervous system deficits. A child might, for
example, routinely sit in a position that compromises his
or her ability to breath because of decreased thoracic
excursion. The child is unlikely to see this as a problem,
but a family member or a member of the health care
team could believe that a problem (NPIP) will develop.
In this case, either the therapist or the caregiver will be
the most likely person to identify the problems. Similarly, patients who have had a stroke may have difficulty
communicating about their problems, and others will
need to identify these problems. Justification for anticipated problems, regardless of whether they are PIPs or
NPIPs, can, in the HOAC II, only be based on theory or
Physical Therapy . Volume 83 . Number 5 . May 2003
arguments that are data (evidence) based. Hypotheses
that guide intervention to eliminate existing problems
(PIPs or NPIPs) can be tested because a change in
something can be measured (eg, changes in impairment
levels and disability). Changes in what is measured will
be identified in the part of the algorithm where reassessment occurs.
A problem is kept from occurring when anticipated
problems are correctly managed. Therefore, no observable change usually relates directly to the problem. More
importantly, in the absence of anything observable or
measurable, a justification based on an outcome is not
possible for interventions aimed at prevention, because
even without intervention a problem may not have
arisen.
Testing criteria are used to examine the correctness of
hypotheses related to problems that currently exist. For
NPIPs or PIPs that are anticipated, however, the therapist establishes predictive criteria, which, if met, indicate
that problems will most likely be avoided because risk
factors were reduced or eliminated. A predictive criterion for a patient with low back pain, for example, may
be that a patient is considered no longer at risk when the
patient can perform stretching exercises at a suitable
level of performance on a regular basis (the predictive
criteria would detail the specific exercise and how often
it should be performed).
To justify any predictive criterion, the therapist should
base the criterion on best available evidence. Patients
with spinal cord injuries, for example, might no longer
be considered at risk (ie, they have achieved the predictive criteria) for developing skin ulcers when they have
shown that: (1) they will spontaneously do wheelchair
pushups a given number of times per hour, and (2) they
will monitor the status of their skin by having someone
check for red marks or abrasions at specified intervals. In
each case, the predictive criteria relate to an observable
behavior, not just increased awareness or knowledge.
The behavior ideally is justified based on identified
evidence or sound theory and not just on assumptions.
Circumstances may make it impossible to achieve goals
with observed behaviors, and in these special circumstances knowledge may be a reasonable predictive criterion (eg, when the therapist cannot visit the patient’s
workplace but teaches the patient strategies for avoiding
injury).
The dual problem lists, one for PIPs and one for NPIPs,
are merged into a single problem list as one proceeds
through the algorithm. Throughout the rest of the
algorithm, the source that identified the problem is not
a concern. What is critical, however, is that therapists
manage anticipated and existing problems differently,
Rothstein et al . 457
and the algorithm provides parallel paths for the management of the 2 types of problems. This is particularly
important in the reassessment phase (Part 2 of the
algorithm). The existence of a list of anticipated problems and the predictive criteria allows for the identification of which interventions are designed for prevention,
how these interventions are justified, and when intervention can be stopped. A novel element of the HOAC II,
one that we believe has not previously been seen in
physical therapy literature, are mechanisms to make
interventions designed for prevention goal oriented and
of determinate duration (ie, there is a stated goal that
must be achieved and there is an expectation as to how
long this will take).
The algorithm provides clinicians with a mechanism for
planning and evaluating activities designed for prevention. This approach encourages therapists to work to
minimize risks through prevention, but, more importantly, it allows them to evaluate their efforts and to
describe and justify their efforts to one another, payers,
managers, and others. Because in HOAC II prevention
activities are goal driven and are planned for specified
periods of time, therapists can, through use of the
algorithm, identify to payers the resources they will need
to achieve prevention. This should, in our opinion,
assure payers that interventions will not continue indefinitely, unless that can be justified before the initiation
of the intervention. The algorithm also allows the therapists to document when, in their professional opinions,
prevention activities are needed and the consequences
of what will occur if these are not carried out (eg, due to
a lack of patient adherence or because they are not
authorized by payers).
In a continued effort to keep focus on what are truly the
patient’s goals, one problem list (the PIP list) is generated before the examination. In the HOAC II, there is a
record, at least initially, of who identified the problem. A
complete problem list, however, including problems
identified by the therapist and others, and a complete set
of goals are not generated until later in the process.
Figures 1 and 2 illustrate Part 1 of the HOAC II.
In Part 2 of the HOAC II, there are 2 reassessment paths,
one for existing problems and one for anticipated
problems (Figs. 3 and 4). In each case, there are
questions on a flow diagram that direct therapists
through relatively simple steps that are taken in response
to questions. Two flow diagrams are used to describe the
reassessment, one for existing problems and one for
anticipated problems. A list of commonly used terms
operationally defined for the HOAC II is provided in the
Appendix.
458 . Rothstein et al
Using the Algorithm
Part 1 of the algorithm deals with all 5 elements of the
patient/client management model described in the
APTA’s Guide to Physical Therapist Practice 6 (examination,
evaluation, diagnosis, prognosis, and intervention). The
Guide is not specific about issues related to the use of an
evaluative strategy to modify interventions and to test
hypotheses. In the Guide, however, under “Intervention,” it is stated: “Decisions about intervention are
contingent on the timely monitoring of patient/client
response and the progress made toward achieving the
anticipated goals and expected outcomes.”6(p46) We
believe, therefore, that Part 2 of our algorithm is an
elaboration on one vital element of what the Guide
refers to as “intervention.” In the HOAC II, issues related
to monitoring intervention effects and altering the plan
of care are covered in Part 2.
Part 1
Collect Initial Data (Includes the History)
Early in an episode of care, clinicians start to obtain
information that they will use to guide all elements of
patient management. Practitioners appear to approach
each patient with a set of hypotheses and collect data to
confirm or refute those hypotheses8,9; therefore, even
initial data collection is hypothesis driven. During the
interview, for example, questions about activities that
may have caused an injury are one sign that the clinician
is seeking to confirm or deny hypotheses. More experienced clinicians can be expected to generate hypotheses
earlier than less experienced practitioners9 and, in our
experience, more effective clinicians often feel a greater
freedom to discard hypotheses and consider alternatives
as early as the interview phase of the patient
examination.
The algorithm does not specify the type and scope of
information gathered during the initial data collection
phase. This remains the choice of clinicians, depending
on their approach to practice. The algorithm simply
requires clinicians to note what they do in this process.
Information that will be used to create a PIPs list needs
to be obtained during the initial data collection.
Patients seeking physical therapy have expectations of
what therapy should offer them, and these may differ
from what their therapists feels are reasonable. A patient
may believe that walking without an assistive device
should be the goal, for example, whereas the therapist
may contend that this would be impossible and walking
with a device would be a reasonable goal. Among the
essential data that clinicians must collect are clear nonmedical descriptions of expectations, particularly
descriptions of those disabilities and functional limitations that need to be eliminated. Incongruence among
Physical Therapy . Volume 83 . Number 5 . May 2003
ўўўўўўўўўўўўўўўўўўўўўўўўўўў
Figure 1.
The initial steps of Part 1 of the Hypothesis-Oriented Algorithm for Clinicians II (HOAC II).
Physical Therapy . Volume 83 . Number 5 . May 2003
Rothstein et al . 459
Figure 2.
The final steps of Part 1 of the Hypothesis-Oriented Algorithm for Clinicians II (HOAC II).
460 . Rothstein et al
Physical Therapy . Volume 83 . Number 5 . May 2003
ўўўўўўўўўўўўўўўўўўўўўўўўўўў
Figure 3.
The algorithm for reassessment of existing problems in Part 2 of the Hypothesis-Oriented Algorithm for Clinicians II (HOAC II).
Physical Therapy . Volume 83 . Number 5 . May 2003
Rothstein et al . 461
Figure 4.
The algorithm for reassessment of anticipated problems in Part 2 of the Hypothesis-Oriented Algorithm for Clinicians II (HOAC II).
462 . Rothstein et al
Physical Therapy . Volume 83 . Number 5 . May 2003
ўўўўўўўўўўўўўўўўўўўўўўўўўўў
expectations of the patient, a payer, a referral source,
and a therapist will be considered when problem lists are
generated, but information about the differing expectations needs to be obtained early in the process.
Generate a PIPs List
Generating the PIPs list is one of the easiest things to do
in the HOAC II. It requires clinicians simply to record
patients’ reports of the problems that led them to seek
physical therapy (or the medical care that led to a
referral for physical therapy). Therapists ask patients
about what they can and cannot do (ie, what limitations
they have in function). A functional limitation or disability is a problem, and, in some cases, patients also may
express concerns that they have a condition that could
lead to the development of loss of function in the future.
In this way, a patient could be the one who identifies an
anticipated problem. The therapist, however, with consultation with the patient, needs to determine whether
the patient’s concern is realistic and, if the anticipated
problem is justified, add it to the problem list.
Because the HOAC II emphasizes accountability, we
believe therapists should never assume that any patient
concern about the future means that an anticipated
problem will occur. Only when the therapist can supply
evidence or a sound theoretical argument to support the
possibility of the anticipated problem occurring should
it be placed on the list, which is true regardless of the
source. Evidence is preferred over theory when the
therapist believes that the patient’s concern about future
events is not warranted. The therapist needs to discuss
the reasons with the patient and, to enhance accountability, document that the discussion took place (ie, if
the patient’s concern was not added to the problem list,
explain why).
Formulate Examination Strategy
Based on the initial data collected and the nature of the
PIPs, the therapist needs to determine what other information is needed. This is an examination strategy, and it
cannot exist independently of hypotheses. When generating the examination strategy, the therapist is not yet
able to identify a best hypothesis as to the cause of the
patients’ problems (both PIPS and NPIPS). The therapist may have several competing hypotheses and needs
to develop an examination strategy that will obtain
information to confirm correct hypotheses and negate
nonviable hypotheses. Unless a therapist has some tentative ideas (hypotheses) as to what may be causing the
problems (eg, the potential impairments or pathologies
causing functional limitations or disabilities), there can
be no examination strategy.
Experienced clinicians appear to generate hypotheses
more readily than less expert clinicians, and they also
Physical Therapy . Volume 83 . Number 5 . May 2003
appear to be better able to identify sources of data
needed for hypothesis testing.10 We believe many new
therapists, like many new physicians, often conduct a
plethora of tests because: (1) they have been taught
methods of patient management that require suspension
of hypothesis generation until all the data are collected,
or (2) they do not have enough experience to generate
a tentative idea (hypothesis) on which to base a focused
examination strategy. We recognize that, for some
patients, therapists may be unable to generate examination strategies, and the algorithm calls for consultation
when this occurs and provides a mechanism for documenting and justifying the use of a consultant.
When using the HOAC II as a guide to documentation,
therapists must describe their examination strategies,
including how they arrived at these strategies (based on
available data) and why they believe the chosen examination techniques will lead to information that can be
used to confirm or deny hypotheses. This may appear to
require a lot of information. Notes in the patient’s
medical record, however, may be as simple as “the
patient’s inability to walk down stairs may be due to
balance problems. Testing of balance appears to be most
important, and tests of muscle force and range of
motion will be conducted to rule out less likely causes of
the functional limitation.” In this example, the balance
testing directly addresses the hypothesis, whereas muscle
force measurements and range-of-motion measurements
could lead to rejection of the hypothesis. The important
element is that a link exists between the logic that guides
the examination strategy, the information available, and
the therapists’ hypothesis. This does not require elaborate documentation on the part of the therapist.
Conduct the Examination and Analyze the Data
Examination procedures for a given type of patient may
be governed by departmental policies, critical paths, or a
variety of other influences. Ideally, approaches should
be data driven (evidence based) and based on research
suggesting best methods of examination and data analysis.11 The HOAC II does not specify how or what to
examine, but, for the process to be useful, the examination must follow logically from the examination strategy
and not include extraneous procedures if they are not
part of the examination strategy. That is, examination
procedures should be related to the tentative hypotheses, either to confirm or to reject those hypotheses. The
measurements obtained during this phase should be of
the type and quality specified by the APTA’s Standards for
Tests and Measurements in Physical Therapy Practice.12
For documentation, all descriptions and analysis of the
data obtained during the examination should be clear.
Reasons why hypotheses were supported or rejected
need to be specified, and, when findings call for addi-
Rothstein et al . 463
tional examination procedures, this should also be
described.
Add NPIPs to the Problem List
Just as existing and anticipated problems are on the PIPs
list, existing and anticipated problems are on the NPIPs
list. The anticipated problems require special consideration because they involve prevention, whereas the current problems are those, including functional limitations
and disabilities, that were not initially described by the
patient. NPIPS may be identified as early as the initial
data collection phase, but they do not formally appear in
the HOAC II until after the examination, when the
NPIPs list is completed.
Sometimes, particularly with children or those with
communication disorders, caregivers or family members
may describe current problems. In this case, the problems may be described in the initial data collection
phase. These problems are placed on the NPIPs list, but,
in the context of the HOAC II, will be managed in a
similar way to the other existing problems on the PIPs
list. The problems are not different in nature, but only in
the source of identification. The therapist, however, is
responsible for the management of the problems on the
NPIPs list regardless of the source that identified the
problem.
Anticipated problems are different than existing problems, and, in the HOAC II, management of anticipated
problems is a central feature. Following a transtibial
amputation, for example, a person is likely to develop a
knee-flexion contracture.13 The therapist is likely to
know this, and the patient is not likely to know this. The
therapist also will know that if a contracture develops,
the patient may be unable to use a prosthesis and may
lose function.
Identification of anticipated problems often requires
therapists to consider anticipated impairments to prevent functional limitations and disability, but anticipated
problems may also be pathologies. A therapist, for
example, should be aware that returning a patient with a
compromised cardiovascular system to full activity without the patient being able to monitor his or her own vital
signs could cause a cerebrovascular accident (CVA) or
myocardial infarction. Here the anticipated problems
are pathologies that could be prevented by teaching the
patient how to monitor his or her cardiovascular status.
The patient also may be the source for anticipated
problems, and, although these are in the PIPs list, they
are managed in a way that is similar, in the context of the
HOAC II, to the way all other anticipated problems are
managed.
Anticipated problems are usually risk factors, for future
pathologies, impairments, functional limitations, and
disabilities. The problem is the risk factor, and the
intervention will be aimed at eliminating the risk factors. Sometimes an exacerbated risk factor may be
contributing to functional limitation or disability. In a
person with low back pain, for example, inappropriate
lifting techniques may be the reason for an existing
problem (ie, activities cause pain, which limits function),
but continued use of poor techniques following the
current episode could lead to recurrence. Poor lifting
techniques may be a cause of an existing problem, and
this needs to be addressed when the therapist generates
hypotheses regarding the causes of existing problems.
The poor lifting techniques also could be the cause of an
anticipated problem because they put the patient at risk
for future disability.
Justification for Hypotheses
The therapist makes 2 types of justification based on the
nature of the problem (existing or anticipated) and
chooses one of 2 paths in the algorithm. Existing problems require one type of argument, that is, hypotheses
about the diagnosis that detail what needs to be changed
to eliminate existing problems. Anticipated problems
require a different kind of justification for the elimination of risk factors and a case as to what may happen
without intervention. Both types of justification should
be evidence based to the extent possible.
Generate a Hypothesis (or Hypotheses) as to Why the
Problems Exist
Each existing patient problem has an underlying cause
or causes. In the HOAC II, the cause is usually due to an
impairment that is present, but in some cases the cause
could also relate to pathology, functional limitations,
societal limitations, or disabilities. Interventions, we
believe, need to be focused on eliminating causes of
problems. However, unless clinicians state, during clinical problem solving and documentation, why they
believe problems exist, it is often difficult to justify
interventions or to see how they relate to problems.
Students, for example, often find it difficult to see how
their clinical instructors determined what intervention
to use. Similarly, payers may not be able to discern why
a therapist focuses on an isolated motor skill instead of a
functional task during intervention unless the therapist
hypothesizes that a relationship exists between the isolated skill and functional activities. The hypotheses generated during this step provide the link between the
therapist’s diagnosis and the intervention. No intervention for an existing problem should be conducted unless
it relates to the hypothesized cause of a problem.
Often the causes of disabilities will be the presence of
pathologies, impairments, and functional limitations.
464 . Rothstein et al
Physical Therapy . Volume 83 . Number 5 . May 2003
ўўўўўўўўўўўўўўўўўўўўўўўўўўў
Many physical therapy interventions focus on impairments and functional limitations, and therefore most
diagnostic hypotheses will be directed at the impairment
and functional limitation dimensions. Sometimes, however, therapists will attempt to eliminate a pathology.
When this occurs, the pathology is the hypothesized
cause. When a therapist believes that a wound fails to
close because of infection, for example, the hypothesis
could be at the level of a pathology; that is, unless the
sepsis is eliminated, the wound will not close. This would
be a testable hypothesis because wound cultures could
be requested. Hypotheses that identify suspected pathologies often cannot be tested by physical therapists
because most therapists are unable to request invasive
tests or radiological diagnostic tests. Therapists usually
need to consult with and possibly refer patients to a
physician to determine when a pathology is identified as
the diagnosis in a hypothesis.10
The HOAC II, like the original algorithm, places an
emphasis on hypothesis generation and requires the
therapist not only to determine what may be causing the
problem (eg, loss of muscle force, loss of motion), but to
also postulate as to the magnitude of the deficits (eg, how
much weakness a patient has and how much force would
be needed for the problem to be eliminated). The
amount of force needed will serve as the testing criteria
for the hypothesis. Therefore, when generating hypotheses, therapists must understand that in a subsequent
step they must quantify what must be achieved to eliminate the problem. One way of determining whether a
hypothesis is appropriate is to consider whether such
testing criteria could be generated. In the wound example, the criteria would be a report of a negative culture.
This example demonstrates that even when the hypothesis is at the level of pathology, generation of testing
criteria must be possible.
Hypotheses that identify impairments as the cause of
disabilities and functional losses are even easier to
generate. If a person cannot walk following a CVA, for
example, it would be incorrect in the HOAC II to
hypothesize that the cause is damage to the motor
cortex. Although this may be true, the quantification of
the type and extent of pathology is not observable and
measurable by physical therapists. The diagnostic
hypothesis may be that the person cannot walk because
he or she lacks the ability to generate sufficient quadriceps femoris muscle force during stance. In this example, the problem is a functional deficit, and the hypothesis relates the functional deficit to an impairment. The
testing criteria will be the amount of force the therapist
believes the patient needs to be able to generate to
eliminate the problem (ie, to walk). Had the hypothesis
identified a pathology (damage to the motor cortex),
the pathology could not be measured by physical thera-
Physical Therapy . Volume 83 . Number 5 . May 2003
pists, and, more importantly, the intervention is not
designed to change the pathology, but rather the impairment and disability that the pathology caused. In addition, the pathology (as measured with magnetic resonance imaging, for example) would likely be
unchanged, even though the intervention successfully
dealt with the impairment or functional limitation.
The critical elements of hypotheses are that they deal
with elements that would be affected by the intervention
and that they must be sufficiently clear to allow for the
generation of testing criteria. The testing criteria that
therapists generate must represent pathology, impairments, or functional loss that can be measured in clinical
practice. As discussed earlier, when a previously undiagnosed pathology is hypothesized to be present, consultation with or referral to a physician may be required to
confirm the hypothesis. A problem may have more than
one underlying cause, and, in these cases, the therapist
may generate multiple hypotheses. The therapist also
would generate testing criteria for each hypothesis. This
might occur, for example, when weakness and a lack of
coordination are hypothesized to be the reasons why a
person can no longer ambulate independently.
For Each Anticipated Problem, Identify the Rationale for
Believing Anticipated Problems Are Likely to Occur
Unless Intervention Is Provided
Physical therapists, like many other health care professionals, share beliefs about what is happening and what
may happen to their patients. Some of these beliefs are
based on data that identify risk factors, factors that once
eliminated should reduce the possibility of future negative health outcomes. The Framingham study, for example, identified many risk factors for cardiovascular disease.14 Epidemiological studies of this type are usually
the means for justifying interventions designed to eliminate risk factors. Unfortunately, data often are lacking
for beliefs that health care professionals have about risk
factors.
On what data do physical therapists act? The question is
a legitimate patient management and resource allocation query. Without evidence to support the value of
elimination of risk factors, the possibility of excessive
intervention exists. Too little intervention for risk factors
also is a possibility. The HOAC II provides a mechanism
for therapists to use either epidemiological data or
theoretical constructs to justify interventions aimed at
reducing risk factors. The former is data based or
evidence based, whereas the latter uses argumentation
and logic that should have some scientific basis.
Evidence-based arguments are preferred.15
By using the algorithm, justification is explicit rather
than implicit and can be discussed by all relevant parties.
Rothstein et al . 465
We contend that unless physical therapists can provide
either good presumptive arguments or data to support
interventions aimed at reducing or eliminating risk
factors, the role of therapists in prevention will be
increasingly challenged and possibly eliminated. When
therapists provide evidence to support their decisions,
however, little reason exists to deny interventions if the
risk-benefit ratio is reasonable. When therapists can only
provide arguments, the case is less clear.
When using the HOAC II, we believe therapists must
discuss all anticipated problems in the documentation
and provide arguments and evidence as to why they
believe that a problem would occur without intervention. This applies to justification for all interventions
related to anticipated problems and diminishes the
likelihood of unnecessary interventions or of interventions continuing after they are no longer necessary. We
believe this documentation will not only enhance patient
care but also will make our interventions more credible,
particularly those aimed at prevention.
Refine Problem List
The problem list at this point in the algorithm contains
2 types of problems (existing and anticipated) derived
from 2 sources (the patient and all other sources). The
therapist needs to determine whether the problems can
be addressed by physical therapy interventions. If the
patient needs the intervention of another health care
practitioner, the therapist needs to make a referral and
document why the referral is necessary. If the therapist
believes that the problem cannot be addressed, such as
when no intervention would help, the therapist needs to
discuss this with the patient and: (1) remove the problem from the list of problems to be addressed by physical
therapy, (2) document why the problem could not be
eliminated, and (3) document the discussion that took
place and describe what was agreed on with the patient.
The therapist may believe that some problems can only
be modified and not be fully eliminated. Again, the
therapist should make this modification in the problem
list, discuss it with the patient, and document the nature
of the discussion.
For Each Problem, Establish One or More Goals
Existing problems. In the HOAC II, like the original
algorithm, there is one type of goal—something that the
patient needs to achieve. Goals are almost exclusively
expressed in terms of functional activities that the
patient wants or needs to perform. Often therapists and
others have used the term “short-term goal” not only to
indicate something that can be achieved in less time
than long-term goals, but also to indicate changes in
levels of impairments they believe are related to longterm goals. A therapist might say, for example, that a
466 . Rothstein et al
short-term goal is teaching the patient an exercise to
strengthen a paretic limb. Strengthening would relate to
a long-term goal in which that limb might be used for
ambulation. We believe this approach is confusing.
Changes in the force-generating capacities of muscles
may indeed help some patients to achieve functional
activities, but the goal is the function—strengthening
may or may not be a means to that end. We contend that
if all a therapist achieves is increased force capacity, the
patient has gained little or nothing from therapy. To
consider a change solely in an impairment as meeting a
goal, in our opinion, is almost always inappropriate.
In the HOAC II, impairment changes are monitored
through the testing criteria and usually are not goals. All
of the goals used in the HOAC II must represent
meaningful accomplishments.16 That is, meeting a goal
as written in the algorithm means the patient’s function
has changed meaningfully. Some functions may be
recovered sooner than others, and these can be identified as short-term goals. The overriding issue is that longand short-term goals represent the same kind of phenomenon (meaningful change for the patient) and the
only difference is the time needed to achieve them. The
simplest way of checking whether a goal is really
meaningful in the HOAC II context is to consider:
(1) whether anyone would feel therapy was worthwhile if
this is all that is achieved and (2) whether the payer
would find therapy to be worthwhile if this is all that is
achieved.
Many patients, such as people with CVAs, may, in theory,
have many problems, and they might have a rather long
list of goals they want to achieve to perform activities of
daily living (ADL), instrumental activities of daily living
(IADL), and other activities. Goal lists for such patients
might seem almost infinite in scope and impractical in
length. For patients such as these, the therapist needs to
work with the patient to identify those goals that are
most important and those that are indicative of various
levels of difficulty. A therapist may list as a goal “independence in brushing teeth,” for example, and use this
to represent a variety of similar tasks requiring eye-hand
coordination, such as using utensils for eating. In this
way, not all goals have to be listed, but rather there
should be those that are especially important to the
patient and those that represent a hierarchy and diversity of motor skills that could serve as goals.
Anticipated problems. Therapists and patients need to
work together to eliminate existing problems to achieve
goals that they have delineated together. The goal for an
anticipated problem is to prevent the problem from
occurring.
Physical Therapy . Volume 83 . Number 5 . May 2003
ўўўўўўўўўўўўўўўўўўўўўўўўўўў
For Each Existing Problem, Establish Testing Criteria
In the HOAC, the word “hypothesis” is used because it
has a mechanism for therapists to test whether their
ideas about causes of problems (ie, their diagnoses) may
be correct. Only controlled studies can provide data as to
whether interventions lead to desired effects. In clinical
practice, however, the issue is whether we can provide
interventions that we believe are effective. We believe
one mechanism by which that can be done is the use of
a systematic approach to patient management. The
HOAC II, we believe, allows such an approach for the
integration and use of the best evidence available. The
HOAC II requires hypothesis testing in clinical practice.
In the context of the HOAC II, the therapist has a
hypothesis as to what is causing a problem, and usually
that is an impairment leading to diminished function.
An impairment is a loss of function in an organ or
system, such as a loss of motion, strength, or coordination. These losses are all measurable. Therefore, if the
intervention is focusing on the cause of the problem, as
the impairments lessen, function should improve. The
problems should be diminishing, and goals should be
closer to attainment. At times, a problem may be hypothesized to be caused by multiple impairments. But how do
we know whether we have identified the correct diagnostic hypothesis?
In the HOAC II, changes in the impairment measure are
almost always monitored. The level of improvement in
impairment that the patient needs to achieve to eliminate the problem is called the “testing criteria.” When
multiple impairments occur, each will have to be measured, with testing criteria established for each. When
testing criteria are met, the problem should have been
eliminated and the related goals achieved. In this way,
the therapist tests the original hypothesis for existing
problems.
For Each Anticipated Problem, Establish Predictive
Criteria
The conceptual basis for the testing criteria comes from
the application of traditional scientific methods of
inquiry into clinical practice. Unfortunately, this cannot
easily be done for anticipated problems. In science,
proving a negative is often seen as impossible because
hypotheses are not testable in the usual sense. If we
intervene to prevent a contracture, for example, we
cannot prove that we achieved anything. The failure of a
contracture to develop may be due to an intervention or
because a contracture would not have developed anyhow. With an anticipated problem, however, we can
argue that, based on what is known, something might
have occurred had we not intervened. Therefore, the
means of justifying interventions focused on prevention
is not in this part of the algorithm, but rather it is
described in the section where therapists supply the
Physical Therapy . Volume 83 . Number 5 . May 2003
rationale for each anticipated problem (see section
titled “For Each Anticipated Problem, Identify the Rationale for Believing Anticipated Problems Are Likely to
Occur Unless Intervention Is Provided”).
The testing criteria for existing problems are used to
examine the viability of the hypothesis. The predictive
criteria for the anticipated problems are different from
the testing criteria. A goal for an existing problem can be
achieved within a known time period. If we are trying to
keep something from happening, when do we declare
we have succeeded? In health care, often the best we can
do is to eliminate risk factors; therefore, the predictive
criteria relate to risk factors. If risk factors can be
eliminated during some finite time period, the predictive criteria would reflect this possibility.
For example, if a patient is seen as being at risk for the
postsurgical development of pneumonia (a pathology),
pneumonia would be an anticipated problem. Physical
therapy interventions may be gait training and breathing
exercises. Both of these interventions are preventive
because they relate to the potential reduction in risk of
pneumonia. The predictive criteria for ambulation may
be a certain distance walked per day, whereas the
predictive criteria for the breathing exercises may be an
inspiratory level with an inspirometer and an observed
level of competence in generating a productive cough.
When these predictive criteria are achieved, the patient
should no longer need the preventive interventions.
This finite situation can be contrasted with people who
have permanent disabilities and chronic injuries who
may have to reduce risk factors for the rest of their lives.
A patient with recurrent back pain, for example, may be
taught prophylactic exercises, and the predictive criteria
may be a level of competence and degree of adherence
in doing those exercises. When the desired level of
competence and adherence is achieved—that is, when
the predictive criteria have been achieved—the patient
would no longer need ongoing physical therapy intervention. The assumption is that the patient would continue to carry out the exercises as taught, or that the
therapist might need to see the patient periodically to
determine whether the predictive criteria are still being
met (ie, the patient is still performing the exercises with
the appropriate frequency and in the proper manner).
The predictive criteria are used to determine how long
interventions designed for prevention should be carried
out. In this way, predictive criteria are somewhat similar
to goals, but they exist only for anticipated problems.
They are not goals because they are worth achieving only
if sufficient evidence indicates that a problem might
occur. The value of achieving the predictive criteria is
Rothstein et al . 467
entirely dependent on the case made for anticipating
that a problem might occur.
Establish a Plan to Reassess Testing and
Predictive Criteria and Establish a Plan to
Assess Problems and Goals
Hypotheses often require multiple testing criteria, and
changes in the impairments measured for these criteria
may not all change at the same rate. Similarly, achievement of various predictive criteria may not happen at the
same time. Measuring impairments and disabilities and
doing a re-evaluation at every session is time-consuming
and impractical. Therapists should have reasonable
expectations as to when meaningful and therefore measurable changes will occur and should plan a
re-evaluation schedule accordingly. Similarly, not all
goals can be achieved at the same time, and therefore
they should be checked based on a logical plan (ie,
short-term goals should be checked sooner than-long
term goals). By committing to an evaluation schedule, a
therapist using the HOAC II has identifiable points in
time when the patient’s status will be reconsidered.
Without such a plan, re-evaluation is often chaotic, and
measurements may be obtained at intervals that may
make interpretation of data difficult.
Plan Intervention Strategy and Tactics
If the therapist thinks muscle weakness is the impairment contributing to a disability, the most obvious
approach would be to use exercise to increase the
force-generating capacity of the involved muscles. The
strategy would be the use of exercise. Describing the
strategy alone is insufficient, because many types of
exercises exist. The HOAC II asks therapists to describe
the tactics (specific exercises and frequency) they would
use. If we were dealing with an anticipated problem
(such as the development of postoperative pneumonia),
there might be 2 strategies: (1) teach the patient how to
clear his or her airway and (2) teach the patient preventive measures such as frequent ambulation and use of an
inspirometer. The tactic for the first strategy (airway
clearance) may be to have the patient cough a specified
number of times per hour (and the patient could be
shown how to determine if the cough is productive). The
tactic for generalized prevention might be correct use of
an inspirometer 5 times daily and ambulation 5 times
daily. Strategies are broad statements of what types of
things need to be done, whereas tactics are the elements
of the intervention. Tactics specify the frequency, duration, and intensity of the interventions.
Implement Tactics
Once tactics have been identified, they need to be
implemented. Most often the therapist will be doing the
implementation. Sometimes, as when a person has a
home exercise program, the patient may be doing the
468 . Rothstein et al
intervention. Family members, other health care personnel (eg, physical therapist assistants), and other caregivers all may have a role in implementing tactics. The
physical therapist, however, should note who is implementing which tactics. We believe the therapist must
recognize that, as long as these tactics are part of the
physical therapy plan of care, the therapist must assume
responsibility for overseeing, evaluating, and determining whether modifications should be made to tactics.
Part 2
In Part 1 of the HOAC II, the therapist working with the
patient and others developed an intervention plan (a
series of strategies and tactics that is conceptually similar
to the plan of care as defined in the Guide).6 Justification for the interventions was based on the therapist’s
concepts of what was causing problems. Therefore, by
definition, much of what occurs in Part 1 arises from
conceptual models that can only be examined in the
context of intervention (eg, did the intervention lead to
a desired outcome?). Part 2 is far less conceptual in
nature and consists of questions that are designed to
provide insights into whether any aspect of patient
management is deficient, including whether the original
goals were viable.
The steps in Part 2 can be used for documentation, or
they can be used to less formally guide decision making.
The most important element, however, is that, by using
Part 2, the therapist must account for all changes in
goals, tactics, strategies, and hypotheses. In addition, the
therapist needs to document whether the criterion measure chosen is still viable and whether it is still reasonable
to expect to see the desired change in the criterion
measure. Part 2 not only assists in the evaluation process,
it provides the logical framework for examining the
effects of all interventions. Use of Part 2 requires the
therapist to document what happened to a patient, even
if the result is an acknowledgment that the result was less
than was expected. Documentation may be particularly
useful on occasions when factors outside of the therapist’s control led to a termination of the intervention.
For example, by following the steps in Part 2, a therapist
can make an argument to a payer that goals were not
achieved (even though progression was being made on
the criterion measure) because there was too little time
allowed for the intervention.
Part 2 consists of 2 flow diagrams. The first diagram
(Fig. 3) leads the therapist through a series of questions
for all existing problems (regardless of who generated
them). The second diagram (Fig. 4) also consists of a
series of questions, but these questions relate to anticipated problems (regardless of who generated the problem list). The peculiar nature of prevention (ie, therapists may take credit for what does not occur by making
Physical Therapy . Volume 83 . Number 5 . May 2003
ўўўўўўўўўўўўўўўўўўўўўўўўўўў
sure a risk factor is reduced or eliminated) leads to
somewhat different questions. The most notable difference is that the first question when dealing with anticipated problems is asking whether the problem has
occurred. If it has, prevention did not work, and a new
problem needs to be added to the existing problem list.
Examining the Hypothesis for Existing Problems
If a patient’s goals are met (the problems are resolved),
the question remains as to whether this occurred
because of the intervention. Although causality cannot
be claimed in the absence of controlled studies, the
algorithm and use of the testing criteria allow therapists
to gain some insights as to whether their approaches
seemed appropriate and their interventions beneficial and
therefore whether their hypotheses were appropriate.
When therapists set the testing criteria, they are stating
that a level of performance (usually of an impairment
measure) is needed for the goal to be achieved. If the
goal is achieved and the testing criteria are not met, the
therapist’s hypothesis is incorrect (or the criteria’s levels
were incorrect). If the testing criteria are met and the
goal is not achieved, the hypothesis is at best incomplete;
that is, other causes may exist in addition to those
identified, or those identified are irrelevant. These are
absolute examples. What is less clear is what is happening when there is movement toward meeting goals and
when there is also an indication that the impairments
measured for the testing criteria are also becoming less
pronounced. In these cases, no simple test of the viability
of a hypothesis exists, so the therapist must extrapolate
and consider the overall picture and determine whether
the hypotheses and criteria should be maintained in the
same form.
When a therapist thinks a problem has multiple causes
and generates multiple hypotheses, it is impossible to say
with certainty whether achieving appropriate levels of all
the testing criteria led to attainment of a goal. The
possibility exists, for example, that if there were 3
hypotheses, 2 of the hypotheses were correct and the
third hypothesis was either redundant or unnecessary.
When all testing criteria are achieved, the therapist has
no way of knowing what would have happened with this
patient if only 2 hypotheses had been met.
Following a CVA, a patient might be incapable of
dressing. Among the many possible causes of this deficit
could be: (1) weakness, (2) lack of coordination, and (3)
poor position sense. All 3 might be hypothesized as
causes of the problem. Testing criteria for weakness
could be a force level obtainable on a hand dynamometer. For the lack of coordination, the testing criteria
might be a level of performance on a coordination test,
and, for position sense, the testing criteria might be the
Physical Therapy . Volume 83 . Number 5 . May 2003
ability to place a limb on a target with less than a
specified number of errors. If all 3 criteria were met and
the patient achieved the goal of dressing himself or
herself, the therapist could not be certain whether this
goal still could have been obtained if only 2 of the 3
testing criteria were met. The therapist, however, may
develop an opinion based on the time course of events;
that is, how did the attainment of the goal over time
relate to changes in the testing criteria? This case
illustrates how, even in the absence of being able to
definitively test hypotheses, therapists can better understand patient management by use of the algorithm. In
this manner, the HOAC II serves as a means of ongoing
feedback for professional development, independent of
what occurs with each patient.
Summary
The HOAC II was designed to facilitate the use of
science and evidence in practice, and to do so in a
manner that is not intrusive on clinical practice. We
believe that much of what we ask clinicians to do in the
algorithm is already part of their practice but that it
occurs in a less defined manner and without a context
for documentation and discussions among colleagues.
Among the differences between this version and the
original HOAC are the mechanisms for justifying prevention and, more importantly, for developing measurable outcomes related to prevention as well as defining
the time it will take to achieve reduction of risk factors.
References
1 Rothstein JM, Echternach JL. Hypothesis-oriented algorithm for
clinicians: a method for evaluation and treatment planning. Phys Ther.
1986;66:1388 –1394.
2 Delitto A, Snyder-Mackler L. The diagnostic process: examples in
orthopedic physical therapy. Phys Ther. 1995;75:203–211.
3 Jette AM. Introduction: physical disability. Phys Ther. 1994;74:379.
4 Jette AM. Physical disablement concepts for physical therapy
research and practice. Phys Ther. 1994;74:380 –386.
5 Feder G, Eccles M, Grol R, et al. Clinical guidelines: using clinical
guidelines. BMJ. 1999;318:728 –730.
6 Guide to Physical Therapist Practice. 2nd ed. Phys Ther. 2001;81:
9 –744.
7 Pope A, Tarlov A, eds. Disability in America: Toward a National Agenda
for Prevention. Washington, DC: National Academy Press; 1991:84 – 89,
223–241.
8 Elstein AS, Shulman LS, Sprafka SA. Medical Problem Solving: An
Analysis of Clinical Reasoning. Cambridge, Mass: Harvard University
Press; 1978.
9 Payton OD. Clinical reasoning process in physical therapy. Phys Ther.
1985;65:924 –928.
10 Goodman CC, Snyder TEK. Differential Diagnosis in Physical Therapy.
3rd ed. Philadelphia, Pa: WB Saunders Co; 2000.
11 Sackett DL, Haynes RB, Guyatt GH, Tugwell P. Clinical Epidemiology:
A Basic Science for Clinical Medicine. 2nd ed. Boston, Mass: Little, Brown
and Co Inc; 1991.
Rothstein et al . 469
12 Task Force on Standards for Measurement in Physical Therapy.
Standards for tests and measurements in physical therapy practice. Phys
Ther. 1991;71:589 – 622.
13 May BJ. Assessment and treatment of individuals following lower
extremity amputation. In: O’Sullivan SB, Schmitz TJ, eds. Physical
Rehabilitation: Assessment and Treatment. 4th ed. Philadelphia, Pa: FA
Davis Co; 2000:632– 633.
14 Dawber TR. The Framingham Study: The Epidemiology of Atherosclerotic
Disease. Cambridge, Mass: Harvard University Press; 1980.
15 Straus SE, Sackett DL. Getting research findings into practice: using
research findings in clinical practice. BMJ. 1998;317:339 –342.
16 Randall KE, McEwen IR. Writing patient-centered functional goals.
Phys Ther. 2000;80:1197–1203.
Appendix.
Terms Used in the Hypothesis-Oriented Algorithm for Clinicians II (HOAC II)
Anticipated Problems:
These can be identified by the patient, the physical therapist, or any
other person and are statements that describe deficits that the therapist
believes will occur if an intervention is not used for prevention.
Examination Strategy:
This is the plan for examination that a physical therapist uses based on
the therapist’s experience, available data relating to the patient, and
information on similar patients. Because not all possible tests and
measures are used, the choice is considered a hypothesis-driven strategy in the HOAC II.
Existing Problems:
These can be identified by the patient, the physical therapist, or any
other person and are statements that describe deficits in a person’s
function (disability).
Goals:
Functional deficits are problems, whereas goals are descriptions of
function that will be recovered as a result of one or more interventions.
Hypothesis:
The reason that a patient’s problems (which are usually at the disability
level) exist is not necessarily known, but in order for a physical therapist
to carry out an intervention, the therapist must have an idea as to the
underlying causes. In the HOAC II, the therapist’s conjecture as to the
cause is a hypothesis. Often there will be more than one hypothesis, and
usually the hypothesis will involve one or more impairments causing a
deficit in function (ie, a disability).
Intervention Strategy:
These are the overall types of interventions that the physical therapist
believes are needed to alleviate problems (eg, exercises designed to
increase range of motion are a strategy, whereas the specific exercises
are tactics).
470 . Rothstein et al
Non–Patient Identified Problems (NPIPs):
These are problems identified (at least initially) by people other than the
patient but that are added to the patient’s problem list after consultation
with the patient (these can be existing or anticipated problems).
Patient-Identified Problems (PIPs):
These are problems identified by the patient (these can be existing or
anticipated problems), and because they are generated by the patient,
they cannot be removed from the problem list without the patient’s
consent.
Predictive Criteria:
These are critical values (thresholds) for measurements, which, if met,
would indicate that one or more problems will most likely be avoided
because risk factors were reduced or eliminated. Sometimes the measurement may be how often someone does a task or whether a patient
demonstrates competency in a prevention program (eg, does stretching
or prophylactic back exercises).
Tactics:
These are the elements of an intervention. For instance, the exercises or
techniques used to treat the patient or client are the specific elements of
the intervention, whereas the overall purpose of the interventions is the
strategy.
Testing Criteria:
These represent critical values (thresholds) for measurements, which, if
achieved, would suggest the hypothesis (or hypotheses) is correct if the
associated problem(s) is resolved (these are most often measurements of
impairments).
Physical Therapy . Volume 83 . Number 5 . May 2003