Psychological Testing: Introduction and History

Psychometrics: Psychological Measurement
Definitions:
- Measurement of mental capacity, thought processes, aspects of personality, etc., especially by mathematical or statistical analysis.
- Science or study of this; construction and application of psychological tests.

Measures a lot of different things
- Mental processes; personality; behaviour; intelligence & cognition; etc.
Aims to operationally define & quantify the things it measures
- e.g. anxiety
- And then be able to predict it
Concerned with constructing tests to measure things
- And evaluating how good these tests are

We can’t measure every aspect of every type of mental process, behaviour, emotional process, etc. that a person has
So we take a sample of that behaviour, through a psychological tests
A psychological test is therefore:
- “a test designed to provide a quantitative analysis of a person's mental capacities or personality traits, typically as shown by responses to a standard series of questions or statements”

A set of items that is designed to measure characteristics of human beings that pertain to behaviour
The process of measuring psychology-related variables by means of devices or procedures designed to obtain a sample of behaviour
A systematic procedure for obtaining samples of behaviour relevant to cognitive or affective functioning, and for scoring and evaluating those samples according to standards

Through test items
- A test question; something a person must do in a test; a task in a test a person must perform etc.
- NB: note that a test items is not necessarily always a question – can be spotting a missing detail in a picture, etc.
Test items are therefore defined as:
- “A specific stimulus to which a person responds overtly”

Individual tests
- Designed to be administered to 1 person at a time
- Useful for collecting comprehensive info
- e.g., some personality tests, some IQ tests
- Usually some degree of subjectivity in the scoring
- Time, cost, labour intensive
Group tests
- Designed to be administered to more than 1 person at a time, i.e. ‘mass testing’
- e.g., university class tests (especially MCQs)
- Scoring is usually more objective
- Economical and time-saving

The Wechsler Adult Intelligence Scale (WAIS)
- Block Design
- Requires blocks to be assembled into a certain pattern
- Testee is given a number of different trials
- A trial refers to a test ‘run’

Card 1
- This card is meant to determine a person's subconscious paranoia level and feelings about body image.
- If someone sees a "bat, butterfly, moth or a female figure," they are said to be normal/average, and there is no problem indicated.
- If a person sees a "Jack-o-lantern, Mask, or the face of an animal," then their response may indicate a sense of paranoia.
- Finally, if someone sees anything derogatory or insulting about the female physique, his/her response indicates that he/she has negative feelings about his or her own body image.

Refers to a person’s past/previous learning
Achievement tests are designed to measure person’s past learning on accomplishment of a task (group tests of achievement)

Aptitude refers to an individual’s potential to learn a specified task under provision of training
Potential for learning or acquiring a new skill
Capability of learning a specific task or acquiring a specific skill

Refers to a person’s general potential to solve problems, adapt to changing circumstances, think abstractly, benefit from experience
Measure general mental abilities
E.g., Stanford-Binet; Raven’s Progressive Matrices; WAIS

Personality Tests
- Measure typical behaviour – traits, temperaments, dispositions, etc.
- Designed to measure a person’s individuality in terms of their unique traits and behaviour
- Tests can help in predicting future behaviour
- E.g., MMPI, Rorschach, TAT, 16PF Questionnaire

Structured (objective)
- Self-report statements
- Choose between 2 or more alternative responses
- e.g., true/false; yes/no; this statement is “not at all like me; a bit like me; somewhat like me; a lot like me” etc.
Projective
- Unstructured; Spontaneous response required of test- takers
- Provides an ambiguous stimulus; response requirements unclear
- Assumes that person’s interpretation of an ambigious stimulus will reflect their unique characteristics
- e.g., Rorschach

Provides ambiguous pics and have to make up a story
Story includes:
- What had led up to event
- What is happening in moment
- Emotions and thoughts of characters
- What outcome of story was
Story content and structure thought to reveal the person’s attitudes, inner conflicts and motives, needs for achievement, power, intimacy, and views
31 pictures in standard TAT

Norm-Referenced Tests
- Test score is judged against the distribution of scores obtained by the other test takers
- This distribution is called the norms
- Compares an individual’s results on the test with statistically representative sample
- Rank the performance of a student in a particular group
Criterion-Referenced Tests
- Compare each individual’s performance to a criterion or expected level of performance
- Testee’s score compared to objectively stated standard of performance on that test
- Establish standard/criterion and marks students against it
- E.g., you need 50% to pass your exams

Psychometrics is the quantitative measurement of mental capacity, thought processes, aspects of personality, etc.
Overt or covert behaviours
Measured by test items
Types of Tests / Mode of Administration:
- Individual Tests
- Group Tests
Categories of Test / Dimension Measured:
- Ability Tests
  - Achievement
  - Aptitude Test
  - Intelligence Test
- Personality Tests
  - Structured
  - Projective
Mode of Interpretation / Performance Assessment:
- Norm-referenced tests
- Criterion-referenced tests