psychometrics
n. the branch of psychology concerned with the quantification and measurement of
mental attributes, behavior, performance, and the like, as well as with the design,
analysis, and improvement of the tests, question
Within psychometrics, Tests are used to measure a wide variety of attributes and
characteristics and among such tests one important classification is made between knowledgebased Tests —i.e., Tests of ability, aptitude, and achievement—and person-based Tests , i.e.,
Tests of personality, clinical symptoms, mood, and attitudes. Rust and Golombok 1999 )
A knowledge-based item is designed to find out whether a particular person knows a particular piece of information,
and such tests measure ability, aptitude, attainment and achievement. The
primary focus of these tests is
to measure an individual's abilities, skills, and knowledge in a particular area. They are
often used for selection and placement purposes, such as in education or employment
contexts. Most educational and intelligence tests are of this type, as are some clinical assessment instruments
Examples of knowledge-based tests are the Wechsler Intelligence Scale for Children (WISC-IV-UK) (Wechsler,
Rust, & Golombok, 2004b), which measures ability, and the Rust Advanced Numerical Reasoning Appraisal
(RANRA) (Rust 2002), which measures numerical ability. The Raven’s Progressive Matrices (Raven 2008) is often
used to assess conceptual ability, having the advantage of being language-free.
While, Knowledge-based tests generally assess maximum performance, on the other hand person-based tests
assess typical performance. A person-based test is usually designed to measure typical performance, whether
personality, clinical symp- toms, mood, interests or attitude. They assess
an individual's characteristics,
traits, and behaviors & These tests aim to measure the unique and relatively stable
aspects of an individual's personality. Accordingly Person-based tests are used for a
wide range of purposes, such as in clinical, counseling, and personnel selection settings.
Examples of person-based tests are Orpheus (Rust 1996d), a general-purpose, work-based personality questionnaire;
the Golombok Rust Inventory of Sexual Satisfaction (Rust & Golombok 1986a and b), which measures clinical
symptoms; the Beck Depression Inventory (BDI) (Beck et al. 1961), which measures mood; and the Strong Interest
Inventory (Harmon Hansen, Borgen & Hammer 1994).
One major difference between these two types of test is that knowledge-based tests are necessarily hierarchical and
cumulative. The development of human know- ledge moves in a particular direction from not knowing to knowing.
Person-based tests carry no such implication. Different personalities and different attitudes are just differ- ent, and
there is no intrinsic implication that to hold one attitude is necessarily better or worse, or more or less advanced,
than the holding of another. A consequence of this difference is that the scoring of knowledge-based items tends to
be unidimensional, the person either gets the right or the wrong answer. The scoring of person-based tests, however,
can go in either direction. Thus, someone with a low score on an extraversion scale would have a high score if the
scale was reversed and redefined as an introversion scale.
It's important to note that both types of tests have their own strengths and
limitations. Knowledge-based tests have the advantage of being highly
objective and reliable, as they measure specific and verifiable knowledge and
abilities. However, they may not accurately measure an individual's potential
for learning and growth, and may not be the best predictors of job or
educational performance. On the other hand, person-based tests tend to be
less objective and reliable, but provide valuable insights into an individual's
personality and behavior.
In conclusion, knowledge-based tests and person-based tests are both
important tools in the field of psychometrics. While they measure different
aspects of an individual, they both provide valuable information for selection,
placement, and personal development. To get the most comprehensive
picture of an individual, it's often best to use a combination of both types of
tests.
Knowledge- based
designed to find out whether a particular
person knows a particular piece of
information
such tests measure ability, aptitude,
attainment and achievement
Person- based
Subjective features of a person
Knowledge-based tests generally assess
maximum performance,
what the respondent has learned in the past
whereas person-based tests assess typical
performance
tests of ability assess their potential for
learning or doing in the future.
are necessarily hierarchical and cumulative.
no such implication that to hold one attitude
is necessarily better or worse, or more or less
advanced, than the holding of another
The scoring of person-based tests, can go in
either direction.
Scoring: of knowledge-based items tends to
be unidimensional, the person either gets the
right or the wrong answer.
Examples: Wechsler Intelligence Scale for
Children (measures ability), and the Rust
Advanced Numerical Reasoning Appraisal
(RANRA)
personality, clinical symptoms, mood,
interests or attitude.
Orpheus (work-based personality
questionnaire); the Golombok Rust Inventory
of Sexual Satisfaction (measures clinical
symptoms); the Beck Depression Inventory
(BDI) (measures mood); and the Strong
Interest Inventory