Major assumptions and fundamental questions in psychological testing

Psychology Testing

The Impact and Importance of Psychological Testing

Defining Psychological Testing

A test is defined as a method or procedure for critical evaluation or as a means of establishing the quality, truth, or presence of something. (Webster's Dictionary, 2011). According to the American Educational Research Association (AERA), the National Council on Measurement in Education (NCME) and the American Psychological Association (APA) (1999), psychological test or psychological testing is a discipline most frequently characterized by the use of behavior samples in order to assess various psychological constructs such as the emotional and cognitive functioning of individuals. The psychological test itself is an instrument most often designed to measure constructs that are not observed, and often involve a series of problems or tasks that the participant or respondent must solve. These tests can resemble questionnaires; however, what makes psychological tests different is that they require the respondents' maximum cognitive performance (AERA, NCME, APA, 1999).

Major Category of Tests and Primary Users

There are several categories of psychological tests to include intelligence quotient tests, and personality tests subdivided into projective and objective tests, to name a few. Intelligence quotient or IQ tests are designed to measure intelligence during the achievement of examination and purportedly measure the level and use of development and ability. These cognitive evaluations are considered norm referenced as a series of tasks are presented to the individual being evaluated and the responses are graded according to prescribed guidelines against the norm; most often composed of individuals with similar demographics. Most often, IQ tests are divided into verbal and non-verbal questions. Some of the more noted IQ test measures include the Stanford-Binet Intelligence Scale, the Woodcock-Johnson Tests of Cognitive Abilities, and the Woodcock-Johnson Tests of Achievement (Pearson Assessments, 2009). Observational tests are another means by which psychological assessment is completed, and reportedly is used in the natural observation of person to environment, and person to person interaction.

Personality tests are psychological measures that are most often divided into projective and objective tests. Objective tests most often use an ordinal scale or true false response to gauge the individual testing against a set of criterion or variables. The responses with an objective test, therefore, are much more restricted due to the construction of the examination. Some common objective tests include the Minnesota Multiphasic Personality Inventory and the Beck Depression Inventory. Projective personality tests, such as the Rorschach tests, allow the respondent to answer inquiry more freely. There has been much debate amongst scholars and practitioners regarding the use of projective tests as there have been questions historically raised regarding the validity of these kinds of examination (Pearson Assessments, 2009).

Reliability, Validity, and the Impact on Psychological Testing

In order for a psychological test to be useful, it must be valid and reliable (Messick, 1995). Validity of psychological tests refers to the extent to which they measure what they posit to measure. It is the degree to which theory and evidence support the interpretations of the scores derived from use of the test (Popham, 2008). Although initially, many attempted to subdivide the evaluation of validity, the modern notion of this concept is that validity is a single construct (Popham, 2008). Validity establishes the contextual framework that defines the parameters and scope of proposed interpretation. The framework provided also gives a rational justification that links the test question to the interpretation (Messick, 1995). According to the APA, there are particular categories of evidence to question or support the validity of an interpretation. Evidence based on:

Test content

Response processes

Relations to other variables

Internal structure

Consequences of testing

Reliability in statistics and psychological testing is the measurement of the consistency of the set of measurements or of that measuring instrument (Meeker & Escobar, 1998). In general, there are several categories of reliability estimates including:

Inter-rater reliability -- any variation in measurement when the measurement is taken by different individuals using the same instrument or method.

Internal consistency reliability -- the consistency of results between items in the same test

Test- retest reliability -- the variation by a single instrument or single individual on the same item and same conditions (Roussen, Gasser & Seifer, 2002).