Lecture 3: Essentials of Test score interpretation Flashcards
Frames of References
specific standard used to judge an individual test score
Raw scores
- summarizes a person’s test performance (dichotomous items, polytomous items)
- conveys no meaning beyond expressing how many items were solved
Two sources of information to derive from frames of reference for test scores
- Norms
2. Performance criteria
Norms
- norm-referenced test interpretation uses standards based on the performance of speicific groups
- test performance ot typical behavior of one or more reference groups
- Typical question: performance of test taker compared to that of others?
Performance Criteria
- test scores are interpreted against the demonstration of “performance”
- assess whether and to what extent the desired levels of mastery or performance criteria have been met (educational and clinal setting)
Norm- Referenced Test interpretation
developmental norms
- ordinal scales based on behavioral sequences
- still in use today with young children
- age vs. theory
- mental scores
- grade equivalent scores
Within-group norms
provide a way of evaluating a person’s performance against the performance of a reference group (place test takers performance within a normal distribution)
The normative sample
- should be representative of the intended population
- needs to be sufficient large
- important: recency (re-norming)
Standardization sample
group of individuals on whom the test is originally standardized in terms of administration and scoring procedures, and developing test’s norms
The normative sample
often used as synonymous with the standardization sample, but can refer to any group from which norms are gathered
Reference group
any group of people against which test scores are compared
Information needed to evaluate the application of a normative sample
- how large is the normative sample?
- when and where was the sample gathered?
- how were individuals identified and selected in this sample?
- who tested the sample? And how did the examniner’s qulaify to test the sample?
- what was the composition of this normative sample? (age, sex, ethinicty, etc.)
Variants (of norms)
- subgroup norms
- local norms
- convenience norms
Subgroup norms
- when large samples are gathered, norms can be seperated into subgroup norms
- formed in terms of any variable that may have a significant impact on test scores or yield comparisons of interest
Local norms
- based on respondents from a specific geographical or institutional setting
Convenience norms
test developers use norms based on a group of people who simply happen to be availabe at the time (for financial constraints?)
Scores used for expressing within-group norms
- Percentiles
2. Standard scores
Percentiles
indicates the percentage of person’s in the reference group who scored at or below a given raw score
- 50th percentile (the median)
Percentiles vs. Percentages
- percentiles reflect the rank or position of an individuals’s performance on a test in comparison to a reference group
- percentage scores reflect the number of correct responses that an individual obtain out of a total number of correct responses
Units are unequal across the range?
- differences are exaggerated in the middle section of the raw score distribution and compressed at the extremes (percentag of poeple who score near the middle is greater)