Unit 13: Testing & Individual Differences
13.3 General Concepts in Testing
A Psychological Test is just a standardized measure of a SAMPLE of a person’s behavior – measure individual differences among people in their abilities, aptitudes, interests, and aspects of personality.
SAMPLING = CAUTION, not the whole story
Issues to Look Into When Deciding the Value of the Test
Standardization – refers to the uniform procedures used in the administration and scoring of a test. Needs to be the same instructions, questions, time limits, environment.
Norms – Norms provide information about where a score on a psychological test ranks in relation to other scores on that test. Psych test tell you where you score relative to other people.
- Percentile score – indicates the percentage of people who score at or below the score one has obtained.
- Standardization group – sample of people the norms are based on- needs to be representative of the whole population
Reliability (consistency) – the measurement consistency of a test
- Test-Retest reliability – estimated by comparing subject’s scores on TWO administrations of the SAME test
- Test-retest reliability relies on being able to figure out CORRELATIONAL COEFFICIENTS – numerical indices of the degree of relationship between two variables
Other measures of RELIABILITY
- Alternate-forms reliability - authenticity stablished by carrying out two different forms of the same test to the same individuals
- Split-half reliability - In split-half reliability we randomly divide all items that purport to measure the same construct into two sets. We administer the entire instrument to a sample of people and calculate the total score for each randomly divided half. the split-half reliability estimate, as shown in the figure, is simply the correlation between these two total scores.
- Internal consistency reliability - Used to assess the consistency of results across items within a test.
- Interrater reliability - Used to assess the degree to which different raters/observers give consistent estimates of the same phenomenon
Validity (accuracy) – ability of the test to measure what it was designed to measure
- Content validity – degree to which the content of a test is representative of the domain its supposed to cover – If I asked government questions on a Psych exam
- Criterion-related validity (predictive validity) – estimated by correlating subjects scores on a test with their scores on an independent criterion (another measure) of the trait assessed by the test. ACT scores have correlated with college acceptance, college graduation, or levels of employment after college. Or AP scores with success in college, despite score on the AP exam.
- Construct validity – the extent to which evidence shows that a test measures a particular hypothetical construct --> Does a Happiness Inventory REALLY measure Happiness?