Measurement Theory and Assessment 1 Flashcards
Psychometrician
Specialist in psychology or education who develops and evaluates psychological tests
Test
A standardised measure for sampling behaviour which describes it using categories or scores
Characteristics of a test
- standardised procedure
- for a specific sample of behaviour
- uses scores or categories
- uses norms or standards
- makes a prediction of non-test behaviour
Norm-referenced test
Performance of the examinee is referenced to standardisation sample
Criterion-referenced test
Determines where the examinee stands, regarding tightly defined educational objectives
Assessment
Appraising/estimating the magnitude of one or more attributes in a person
Group tests
Suitable to the testing of large groups of individuals simultaneously (e.g. pen-and-paper tests)
Individual tests
Designed to be administered one-on-one
Types of psychological tests
- intelligence tests
- aptitude tests
- achievement tests
- creativity tests
- personality tests
- interest inventories
- behavioural procedures
- neuropsychological tests
Responsibilities of test publishers
- publication and marketing issues
- competence of test purchasers
Responsibilities of test users
- best interests of the client
- confidentiality and the duty to warn
- expertise of the test user
- informed consent
- obsolete tests and the standard of care
- responsible report writing
- communication of test results
- consideration of individual differences
Diagnostics
Getting to know a situation in order to be able to make a decision
Psychodiagnostics
Getting to know an individual’s psychosocial functioning
- reliable and valid description of their psychosocial reality
- find possible explanations for problems
- test possible explanations
Scientific diagnostics
- ideally repeatable
- ideally approach reality
Uses of tests
- problem analysis
- classification and diagnosis
- treatment planning
- program/treatment evaluation
- self-knowledge
- scientific research
Committee on tests and testing in The Netherlands (COTAN)
Criteria
- principles of test construction
- goal
- group
- function
- standardisation
- quality of test material
- quality of test manual
- norms: representative reference group
- reliability: consistency, repeatability
- validity: does the test assess what it aims to?
Tests need to:
- be relevant
- be performed by qualified individuals
- have role integrity
- be confidential
- have informed consent
- be independent and objective
Classical test theory
Test scores are influenced by two factors: consistency factors and inconsistency factors
X = T +e
Sources of measurement error
- item selection: choosing an instrument/parts of an instrument
- test administration: general environment aspects, countenance of an examiner
- test scoring: subjectively scored tests are vulnerable to mistakes/bias from the scorer
- systematic measurement error: consistent error where something unwanted is measured
Correlation coefficient (r)
Degree of linear relationship between two sets of scores obtained from the same people
Range: -1.00 to 1.00
Positive correlation (r > 0.00) or negative correlation (r < 0)
The closer r is to 1 (as an absolute value), the stronger the relationship
Test-retest reliability
Administering an identical test to the same sample group
Alternate forms reliability
Two tests are independently created to measure the same thing; typical have same (or similar) means and standard deviations; correlation of test groups (from the same sample group) should be strong and positive
Split-half reliability
Correlate scores from the 1st and 2nd half of a test to each other (instead of administering 2 tests)
Spearman-Brown formula
Corrects for the underestimation of reliability when using split-half reliability
Coefficient alpha (Cronbach’s alpha)
Mean of all possible split-half coefficients, corrected by the Spearman-Brown formula
Range: 0.00 to 1.00
Index of internal consistency of the items; tendency for items to correlate positively
Kuder-Richardson formula
Similar to Cronbach’s formula, used for tests with only two answer options
Interscorer reliability
A sample of tests is independently scored by two or more examiners; scores for the tests from each examiner are correlated (should have a strong, positive correlation). Used for subjective scoring tests
Systematic errors
- either positive or negative
- average measurement error is not 0
- can be due to test construction/an inconsistency in the assessed construct
- serve as a measure of validity - how well is the test measuring what it is supposed to
Unsystematic erros
- are random and unpredictable
- are both positive and negative
- average measurement error is 0
- are not related to the true score
- are a measure of reliability - affects the consistency of scores
Raw score
Most basic information provided by a psychological test
e.g. how many questions were answered correctly
Norm group
Sample of examinees, representative of the population for whom the test is intended