Mastering Modern Psychological Testing
Chapter 1: Introduction to psychological assessment
Introduction:
It is likely that someday you will engage in assessment to some degree, or at least need to understand the
outcome of testing and assessment activities. That is why it is important to know at least some of the basics of
the processes involved in testing and assessment.
Brief history of testing: earliest testing
The earliest documented use of tests (circa 2200 BC) is usually attributed to the Chinese who tested public
officials to ensure competence, so it was sort of a “civil service” test.
Brief history of testing: 18th and 19th century testing
Gauss found that in astronomy his colleagues often came up with slightly different locations when tracking
stars. He also came up with the Normal curve and Normal distributions (Gaussian curve). Although he is not
typically recognized as a pioneer in testing, his formal recognition of measurement error and its distributional
characteristics earns him this recognition.
In the late 18th and early 19th century civil service examinations and test similar to those used in China
were introduced in European countries to select government employees.
In the 19th century physicians and psychiatrists developed classification systems to help classify
individuals with mental retardation and other mental problems.
In the brass instrument era, early experimental psychologists like Wundt, Galton, Cattel and Wissler
made significant contributions to the development of cognitive ability testing. An important development was
the move toward measuring human abilities using objective procedures that could be replicated.
Galton is often considered the founder of mental tests and measurement and was responsible for the
first large-scale systematic collection of data on individual differences. Data collection included physical,
sensory and motor measurements.
Cattel shared Galton’s belief that simple sensory and motor tests could be used to measure intellectual
abilities. He and Galton contributed to the development of testing procedures such as standardized
questionnaires and rating scales that later become popular techniques in personality assessment.
Wissler largely discredited the work of his famous teacher Cattel. He found that the sensory-motor
measures used to assess intelligence had no correlation with academic achievement and that sensory-motor
tests had weak correlations with one another. These findings ended the use of sensory-motor measures of
intelligence and set the stage for a new approach that emphasized more sophisticated higher order mental
processes.
Brief history of testing: 20th century testing
Alfred Binet pioneered the use of measures of higher order cognitive processes to assess intelligence. In the
1900s he developed a test to predict academic performance known as the Binet-Simon Scale. It had some
sensory-perceptual tests, but the emphasis was on verbal items assessing comprehension, reasoning, judgment
and short-term memory. The scale was later translated and standardized in the US which resulted in the
Stanford-Binet Intelligence Scale. Intelligence testing received another boost in the US for screening people
who had to join the army. These tests were called the army alpha (verbal) and army beta (nonverbal) test.
Furthermore, Woodworth developed the first formal personality test and Rorschach developed the
Rorschach inkblots in the 1920s. Intelligence testing received another boost in the 1930s when Wechsler
developed an intelligence test that included measures of verbal ability and nonverbal on the same test.
Intelligence tests before this one typically assessed on of the two but not both. The Wechsler Scales have
become the most popular intelligence tests in use today.
In the 1940s the Minnesota Multiphasic Personality Inventory (MMPI) was published to aid in the
diagnosis of psychiatric disorders. It is an objective personality test and its second edition (MMPI-2) continues
to be one of the most popular personality assessments in use today.
,Test, measurement and Assessment:
A test is a device or procedure in which a sample of an individual’s behaviour is obtained, evaluated and scored
using standardized procedures. Because a test is only a sample of behaviour, it is important that tests reflect a
representative sample of the behaviour you are interested in. A standardized test is a test that is administered,
scored and interpreted in a standard manner. The goal is to ensure that testing conditions are as nearly the
same as possible for all individuals taking the test in order for the assessment results to be comparable.
Measurement is defined as a set of rules for assigning numbers to represent objects, traits, attributes
or behaviours. In turn, these numbers are interpreted as reflecting characteristics of the test taker.
Assessment is defined as systematic procedure for collecting information that can be used to make
inferences about the characteristic of people or objects. Assessment should lead to an increased understanding
of these characteristics. Assessment typically refers to a process that involves the integration of information
obtained from multiple sources using multiple methods. This makes it a broader and more comprehensive
process than testing. In actual practice many professionals use testing, measurement and assessment
interchangeably.
There are also a few other important terms. Evaluation is a term used when discussing assessment,
testing, and measurement issues. It is an activity that involves judging or appraising the value of worth of
something. Psychometric properties of a test are the measurement or statistical characteristics of a test which
involves reliability and validity. Reliability refers to the stability or consistence of test scores, so it is the degree
to which test scores are free from measurement error. Validity refers to the accuracy of the interpretation of
test scores.
Types of tests:
Crohnbach noted that tests generally can be classified as measures of either maximum performance or typical
response. Maximum performance tests are designed to assess the upper limits of the examinee’s knowledge
and abilities, examples are intelligence tests and classroom achievement tests. Typical response tests attempt
to measure the typical behaviour and characteristics of examinees. They are often referred to as personality
tests in which the term personality is broadly used for noncognitive characteristics.
Maximum performance tests:
Maximum performance tests are designed to assess the upper limits of the examinee’s knowledge and abilities.
In this category there are a number of subcategories in which the maximum performance tests can be classified
such as:
Achievement vs. aptitude tests
o Achievement tests = measures knowledge/skills in an area in which instruction has been
provided
o Aptitude tests = measures cognitive abilities/ skills that are accumulated as the result of
overall life experiences.
Objective vs. subjective tests
Speed vs. power tests
o Speed tests = performance reflects differences in the speed of performance
o Power tests = performance reflects difficulty of the items the examinee is able to answer
correctly
Typical response tests:
Typical response tests attempt to measure the typical behaviour and characteristics of examinees. When
describing personality tests, assessment experts distinguish between:
Objective vs. projective tests
o Objective tests = items are used that are not influences by the subjective judgement of the
person scoring the test.
o Projective tests = involves the presentation of ambiguous material that elicits in almost
infinite range of responses. Most of these tests involve subjectivity in scoring.
, Types of scores:
There are two fundamental approaches to understanding scores:
1. Norm-referenced score = interpretations compare an examinee’s performance to the performance of
other people, often those in the standardized sample
* e.g. “this student scored better than 95% of his or her peers”
2. Criterion-referenced score = interpretations compare an examinee’s performance to a specified level
of performance
* e.g. “this student correctly answered 95% of the items on the classroom test”
Norm-referenced interpretations are relative to the performance of other examinees whereas criterion-
referenced interpretations are absolute.
Assumptions of psychological assessment:
There are some basic assumptions that underlie psychological assessment:
1. Psychological constructs exist
2. Psychological constructs can be measured
3. Although we can measure constructs, our measurement is not perfect
4. There are different ways to measure any give construct
5. All assessment procedures have strengths and limitations
6. Multiple sources of information should be part of the assessment process
7. Performance on tests can be generalized to non-test behaviours
8. Assessment can provide information that helps psychologists to make better professional decisions
9. Assessment van be conducted in a fair manner
10. Testing and assessment can benefit individuals and society as a whole
Common applications of psychological assessment:
Tests and other assessments have many uses, but underlying practically all of these uses is the belief that they
provide information about important psychological constructs, and that this information can help psychologists
and other professionals make better decisions. Below are brief descriptions of prominent applications of
assessment procedures.
Diagnosis is implied when a health care professional specifies the nature and/or cause of a disorder,
disease, or injury. In psychology, the diagnostic process typically incorporates information obtained using a
variety of assessment procedures and utilizes the DSM as the guiding taxonomy.
Repeated testing or measurement of a variable targeted for change can reveal the relative
effectiveness of a treatment and can give helpful information for treatment planning
Psychological and educational assessment can provide information that promotes self-understanding
and helps individuals plan for their future.
Educators often use a variety of assessment procedures to monitor academic progress of their
students. For example summative evaluation which is the formal evaluation of student performance and often
assigning a numerical or letter grade. Formative evaluation involves evaluative activities that are aimed at
providing feedback to students. Furthermore, testing is also used in licensing decisions, program evaluation and
in scientific methods.
Chapter 2: The Basic Statistics of Measurement
What is measurement?:
Measurement is defined as a set of rules for assigning number to represent objects, traits, attributes or
behaviour. Psychological tests are measuring devices and thus involve rules for assigning numbers to an
individual’s performance that are interpreted as reflecting characteristics of the individual. The units of
measurement that have a mathematical property is called “the scale of measurement”. A scale is a system or
scheme for assigning values or scores to the characteristics being measured. Stevens proposed a taxonomy that
specified four scales of measurement:
1. Nominal scales = qualitative system for categorizing people or objects into categories/classes/sets.
Numbers in this case don’t have meaning and therefore these scales can’t be used for statistical
procedures.
