Supplemental Materials
The Meaning and Measurement of Work Fatigue: Development and Evaluation of the
Three-Dimensional Work Fatigue Inventory (3D-WFI)
by M. R. Frone & M.-C. O. Tidwell, 2015, Journal of Occupational Health Psychology
http://dx.doi.org/10.1037/a0038700
Evaluation of Prior Work Fatigue-Related Measures
The six instruments to be examined here were developed to assess work fatigue, or some
aspect of it, such as work exhaustion (i.e., extreme tiredness). Although these measures were not
developed to provide a broad assessment of work fatigue, as defined in the main article, it is
useful nonetheless to determine the extent to which their underlying conceptual definitions and
items represent work fatigue.
Maslach burnout inventory (MBI). The first version of the MBI was developed in
1981 for human services occupations (MBI-HSS) and contained a nine-item measure to assess
emotional exhaustion (Maslach & Jackson, 1981). A second version of the MBI was developed
in 1986 for educators (MBI-ES) and contained the same nine-item measure of emotional
exhaustion (Maslach, Jackson, & Leiter, 1996). A third version of the MBI was developed in
1996 for other (i.e., general) occupations (MBI-GS; Maslach et al., 1996), which contained a
five-item measure of exhaustion. The original nine-item measure of emotional exhaustion (MBIHSS, MBI-ES) and the revised five-item measure of exhaustion (MBI-GS) will be evaluated in
turn.1
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We do not provide the same level of item detail for the MBI measures as we do for the other fatigue measures
reviewed here. The reason is that the MBI is a commercial product and we want to avoid copyright infringement.
Nonetheless, to better understand our critique of the original emotional exhaustion measure, the interested reader can
see all nine items in Maslach and Jackson (1981). The revised five item measure of exhaustion represents a subset
of these nine items.
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Maslach et al. (1996) defined emotional exhaustion as representing “feelings of being
emotionally overextended and exhausted by one's work” (p. 4). Maslach et al. (1996) also stated
that “the emotional exhaustion scale measures the depletion of emotional energy, distinct from
physical exhaustion or mental fatigue” (p. 20). The definition of emotional exhaustion seems to
capture the tiredness aspect, but not the reduced functional capacity aspect, of emotional work
fatigue. In terms of the items, only one of the nine items directly assesses emotional tiredness (I
feel emotionally drained from my work). Three items assess overall work-related tiredness that
may represent mental or physical work tiredness, rather than or in addition to emotional
tiredness. These three items capture feeling used up by day’s end or feeling fatigued first thing
in the morning or feeling burnout from one’s work. Therefore, these three overall tiredness
items seem inconsistent with Maslach et al.’s (1996) claim that their measure assesses emotional
exhaustion distinct from physical and mental exhaustion. The remaining five items seem to
assess other constructs that are potential causes or outcomes of work exhaustion, such as feeling
frustrated by one’s job, being at the end of one’s rope, feeling that one works too hard, and
feeling stress resulting from working with people. In summary, the nine item measure includes
four tiredness items likely representing an assessment of overall work exhaustion (tiredness)
rather than the specific dimension of emotional work exhaustion, as well as five items that may
represent other constructs. No items assess the reduced functional capacity aspect of emotional
or overall work fatigue.
Although the original MBI was developed for use with human services, including
educational, occupations, Maslach et al. (1996) note that the inventory was used with other types
of occupations almost from the beginning. Therefore, the MBI (MBI-HSS, MBI-ES) was
revised in order to be used with a broader set of occupations (MBI-GS). During this process, the
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emotional exhaustion measure was revised and renamed exhaustion. Although Maslach et al.
(1996) never provided an explicit definition of exhaustion, dropping the adjective emotional
suggests that the revised measure was meant to assess overall exhaustion (tiredness), which can
include physical and mental exhaustion. This is consistent with Schaufeli and Taris’ (2005,
p.258) claim that “MBI-GS exhaustion refers to work-related fatigue.”
Although there were a few minor wording changes, the revised five-item measure
primarily represents a shortened version of the original nine-item measure. The four items that
were dropped were among the five items, noted earlier, that may fail to assess emotional or any
other type of work exhaustion. Of the five retained items, one item directly assesses emotional
exhaustion and three items assess overall work-related exhaustion. To the extent that the intent
of the revised measure was to assess overall work exhaustion (tiredness), these four items show
reasonable fidelity to the intended construct. However, the fifth item was among those, noted
earlier, that may not directly represent work exhaustion (i.e., experiencing stress from working
with people). In summary, compared to the original measure of emotional exhaustion, the
revised measure of exhaustion eliminates most, but not all, of the potential measurement
contamination. This revised measure, therefore, represents an assessment of overall work fatigue
that captures the tiredness aspect of fatigue if the problematic item is dropped from the measure.
None of the items assess the reduced functional capacity aspect of work fatigue.
Oldenburg burnout inventory (OLBI). This job burnout inventory includes an eightitem measure of exhaustion (Demerouti, Bakker, Vardakou, & Kantas, 2003). Demerouti and
colleagues (2003) provided the following definition: “Exhaustion is defined as a consequence of
intensive physical, affective, and cognitive strain, i.e., as a long-term consequence of prolonged
exposure to certain job demands” (p. 14). Although this statement identifies possible causes of
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exhaustion, it does not explicitly define exhaustion itself. Demerouti et al. (2003) stated that the
OLBI’s exhaustion measure assesses emotional, mental, and physical aspects of exhaustion.
Given the wording of many of the items, it appears that the intent of the measure is to assess
overall work exhaustion. Of the eight items, one item directly assesses emotional tiredness
(During my work, I often feel emotionally drained) and three items assess overall tiredness (e.g.,
There are days when I feel tired before I arrive at work; After working, I have enough energy for
my leisure activities [reverse scored]; and After my work, I usually feel worn out and weary). To
the extent that the intent of the measure was to assess overall work exhaustion, these four items
show high fidelity to the intended construct. Collectively, the four tiredness items would
indirectly capture physical, mental, and emotional exhaustion, though it would not be possible to
determine the extent to which each of the three types of fatigue are experienced in a sample of
individuals or represented in the overall exhaustion score. The remaining four items, however,
seem to represent potential causes, outcomes, or correlates of work exhaustion, such as inability
to relax or unwind after work (After work, I tend to need more time than in the past in order to
relax and feel better), ability to manage one’s work load (I can tolerate the pressure of my work
very well [reverse scored]; Usually, I can manage the amount of my work well [reverse scored]),
and work-related vigor (When I work, I usually feel energized [reverse scored]). In summary,
four items assess overall work exhaustion or tiredness and four items seem to represent other
constructs. No items assess the reduced functional capacity aspect of work fatigue.
Copenhagen burnout inventory (CBI). This inventory assesses three constructs—
personal burnout, work burnout, and client burnout. Given the focus of the present study, the
personal burnout measure is not discussed. Kristensen, Borritz, Villadsen, and Christensen
(2005) stated that “the core of burnout is fatigue and exhaustion” (p. 196, italics in original).
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Although these researchers define the two dimensions of burnout in terms of work fatigue, they
do not provide an explicit definition of fatigue or exhaustion. Work burnout is defined as “The
degree of physical and psychological fatigue and exhaustion that is perceived by the person as
related to his/her work” (Kristensen et al., 2005, p. 197). It appears the intent of the work
burnout measure was to assess overall work-related exhaustion (tiredness). Of the seven work
burnout items, one item assesses emotional tiredness (Is your work emotionally exhausting?) and
five items assess overall tiredness (e.g., Do you feel burnout because of your work; Do you feel
worn out at the end of the workday?; Are you exhausted in the morning at the thought of another
day at work?; Do you feel that every working hour is tiring for you?; Do you have enough energy
for family and friends during leisure time? [reverse scored]). However, the final item represents
a construct other than work exhaustion (Does your work frustrate you?).
Client burnout is defined as “The degree of physical and psychological fatigue and
exhaustion that is perceived by the person as related to his/her work with clients” (Kristensen et
al., 2005, p. 197). The intent of the client burnout measure was to assess overall work fatigue
due to working with clients. Of the six items in the client burnout measure, one item assesses
overall tiredness due to working with clients (Does it drain your energy to work with clients?).
Two items seem to partially capture reduced functional capacity (Are you tired of working with
clients?; Do you sometimes wonder how long you will be able to continue working with clients?).
The remaining three items in the measure assess problems related to working with clients that
may be a cause of fatigue, but do not seem to capture client-related work fatigue per se (Do you
find it frustrating to work with clients?; Do you find it hard to work with clients?; Do you feel
that you give more than you get back when you work with clients?).
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In summary, although work fatigue and exhaustion was never explicitly defined, the work
burnout and client burnout measures seem to partially assess overall work fatigue and overall
work fatigue due to working with clients, respectively. The work burnout measure generally
assesses the tiredness aspect of overall work fatigue. The client burnout measure provides some
assessment of both tiredness and reduced functional capacity with respect to overall fatigue due
to working with clients. However, both measures have items that may represent other constructs.
Occupational fatigue exhaustion recovery scale (OFER). This instrument contains
separate assessments of chronic and acute work fatigue. Winwood and colleagues (Winwood,
Winefield, Dawson, & Lushington, 2005, p. 594; Winwood, Lushington, & Winefield, 2006, p.
382) provide a definition of chronic work fatigue taken from Meijman and Schaufeli (1996),
stating that such fatigue represents “an enduring trait characterized by: ‘. . . inefficient action
patterns; declining interest, involvement and commitment; reduced concentration and
motivation; and negative emotions’.” This conceptual definition captures the reduced functional
capacity aspect of work fatigue, though the inclusion of negative emotions introduces
definitional contamination. However, this definition does not capture the extreme tiredness
aspect of work fatigue. In terms of the chronic work fatigue measure, all five items fail to
capture the intended construct. Rather, they appear to assess a variety of potential causes (e.g.,
Too much is expected of me in my work) and outcomes of work fatigue (e.g., I often feel I’m “at
the end of my rope” with my work; I often dread waking up to another day of my work).
Winwood and colleagues (Winwood et al., 2005, 2006) did not explicitly define acute
work fatigue except to suggest that it should be more transient in nature than chronic work
fatigue. The acute work fatigue measure has five items that better represent an assessment of
chronic overall work fatigue (e.g., After a typical work period, I have little energy left; I usually
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feel exhausted when I get home from work; My work drains my energy completely every day).
Each of the acute work fatigue items assess the tiredness aspect of chronic work fatigue and no
items assess the reduced functional capacity aspect of either acute or chronic work fatigue.
Although the acute work fatigue items seem to assess the chronic experience of work fatigue,
they are not consistent with the definition of chronic work fatigue presented earlier by Winwood
and colleagues because the items assess the tiredness aspect of work fatigue rather than the
reduced functional capacity aspect specified in the definition.
Burnout measure (BM). This instrument includes separate assessments of physical,
mental, and emotional exhaustion (Pines & Aronson, 1988). Physical exhaustion is defined as
the experience of “low energy, chronic fatigue, and weakness” (Pines & Aronson, 1988, p. 12).
This definition seems to conceptualize physical exhaustion in terms of overall fatigue rather than
physical fatigue, and it captures tiredness but not reduced functional capacity. The seven items
assessing physical exhaustion include one item directly assessing physical tiredness (Being
physically exhausted). The remaining six items assess overall tiredness that may represent
cognitive and emotional exhaustion rather than or in addition to physical exhaustion (e.g., Being
weary; Being tired; Feeling “wiped out”).
Mental exhaustion is defined as the experience of “negative attitudes toward one’s self,
work, and life itself” (Pines & Aronson, 1988, p. 13). This definition does not actually
characterize common use of the word exhaustion. The seven items are consistent with the
proposed definition of mental exhaustion in that the items reflect overall unhappiness (e.g., Being
unhappy; Being happy [reverse scored]; Feeling optimistic [reverse scored]) and low self-worth
(e.g., Feeling worthless; Feeling rejected). Although overall unhappiness and low self-worth
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may correlate with mental exhaustion (tiredness) or the reduced functional capacity aspect of
mental fatigue, the items do not directly assess mental exhaustion or fatigue.
Emotional exhaustion is defined as the experience of “feeling helpless, hopeless, and
entrapment” (Pines & Aronson, 1988, p. 13). This definition fails to characterize common use of
the word exhaustion. Of the seven items, one item directly assesses emotional tiredness (Being
emotionally exhausted). The remaining six items seem consistent with the proposed definition of
emotional exhaustion in that they assess negative affect and hopelessness (e.g., Feeling
depressed; Feeling anxious; Feeling hopeless). Although negative affect, hopelessness, and
helplessness may correlate with emotional exhaustion (tiredness) or the reduced functional
capacity aspect of emotional fatigue, six of the seven items do not directly assess emotional
exhaustion or fatigue.
In summary, although the BM was purportedly developed to assess physical, mental, and
emotional exhaustion, none of the definitions characterize and none of the measures provide a
direct assessment of these three constructs. Also, neither the measurement instructions nor the
wording of the items connect the items to the workplace. This is consistent with Malach-Pines’
(2005) statement that the measure was developed “for use with all occupations as well as nonoccupational groups” (p. 79).
Shirom-Melamed burnout questionnaire (SMBQ). This instrument contains separate
measures of physical fatigue, emotional exhaustion, and cognitive weariness (Shirom &
Melamed, 2006). Physical work fatigue is defined as “feelings of tiredness and low levels of
energy in carrying out daily tasks at work” (Melamed, Shirom, Toker, Berlinger, & Shapira,
2006, p. 330). However, the core of this definition could just as easily be used to define mental
or emotional work fatigue because it does not refer explicitly to physical tiredness or low
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physical energy. Therefore, the definition might better reflect overall work tiredness. Of the six
items used to assess physical work fatigue, only one item directly assesses physical tiredness (I
feel physically drained). Of the five remaining items, four items assess overall work tiredness
that may represent mental and emotional work fatigue rather than or in addition to physical work
fatigue (e.g., I feel tired; I feel like my “batteries” are “dead”; I have no energy for going to
work in the morning; I feel burned out), and one item that assesses annoyance or discontent
rather than physical work fatigue (I feel fed up). No items capture the reduced functional
capacity aspect of overall or physical work fatigue.
Cognitive weariness is defined as “feelings of slow thinking and reduced mental agility”
(Melamed et al. 2006, p. 330). This conceptual definition seems to capture the reduced
functional capacity of mental work fatigue, but does not capture the extreme tiredness aspect.
The five items represent the reduced functional capacity aspect of mental work fatigue (e.g., My
thinking process is slow; I have difficulty concentrating; I feel I’m not thinking clearly; I feel I’m
not focused in my thinking; I have difficulty thinking about complex things). Consistent with the
definition, no items assess the extreme tiredness aspect of mental work fatigue.
Emotional exhaustion is defined as “feeling that one lacks the energy needed to invest in
relationships with other people at work” (Melamed et al., 2006, p. 330). This conceptual
definition appears to capture the tiredness aspect (lack of energy) of emotional work fatigue, but
does not capture the reduced functional capacity aspect. In contrast, the three emotional
exhaustion items represent the reduced functional capacity aspect of emotional fatigue, but fail to
capture the tiredness aspect of emotional work fatigue specified by the conceptual definition
(e.g., I feel that I am not capable of investing emotionally in coworkers and customers; I feel I
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am unable to be sensitive to the needs of coworkers and customers; I feel I am not capable of
being sympathetic to coworkers and customers).
In summary, the SMBQ assesses the tiredness aspect of overall (rather than physical)
work fatigue and the reduced functional capacity aspect of mental and emotional fatigue. None
of the measures assessed both the extreme tiredness and reduced functional capacity aspects of
work fatigue.
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