Psychometrics, Measurement Scales, Reliability, and Validity

Comprehensive vocabulary flashcards covering basic measurement theory, formulas, reliability types, validity categories, measurement scales, the normal curve, and key historical figures from the lecture notes.

Z-Score

A score that indicates how far an individual score is from the mean in standard deviation units, calculated as $z = \frac{X - M}{SD}$.

$$O = T + e$$

The standard measurement model formula where $O$ represents the Observed Score, $T$ represents the True Score, and $e$ represents Measurement Error.

Reliability

Refers to the consistency of measurement and addresses whether the results of a test can be trusted consistently.

Temporal Reliability

A category of reliability that evaluates the consistency of test measurement over time.

Test-Retest Reliability

The gold standard of temporal reliability where the same test is given to the same group across two time points (Time 1 to Time 2) to compare scores.

Alternate Forms Reliability

A reliability method that measures consistency by using two different but equivalent versions of a test (such as Form A and Form B) and comparing scores.

Internal Reliability

Evaluates whether the different parts or items within a single test consistently measure the same concept.

Split-Half Reliability

An internal reliability method where a test is split into two halves (such as odd-numbered versus even-numbered items) and the results are compared.

Cronbach's Alpha

A statistical measure of internal reliability that determines whether all items on a test work together consistently.

Interrater Reliability

Also called interscorer reliability, it measures the degree of agreement between different raters or psychologists scoring the same assessment.

Validity

Refers to accuracy and whether a test actually measures the psychological construct it is intended to measure.

Content Validity

The degree to which a test adequately covers all representative aspects of the content domain it is designed to measure.

Criterion-Related Validity

Evaluates how well a test's scores relate to or predict an outside outcome or external criterion.

Construct Validity

Assesses whether a test accurately measures the theoretical psychological construct (e.g., intelligence, depression, anxiety, memory, motivation) it claims to measure.

Factor Analysis

A method used in construct validity to evaluate whether individual items group together in ways that support the proposed underlying constructs.

Convergent Validity

A component of construct validity showing that a test correlates strongly with other existing measures of similar constructs.

Divergent Validity

A component of construct validity showing that a test has low correlations with measures of different or unrelated constructs.

Extravalidity

A concept listed under construct validity that examines whether a test's results relate appropriately to external outcomes and provide practical utility.

Face Validity

The extent to which a test appears on the surface to measure what it claims to measure, though it does not serve as proof of actual validity.

Nominal Scale

A scale of measurement that classifies data into distinct, non-numerical categories.

Ordinal Scale

A scale of measurement defined by rank and order.

Interval Scale

A scale of measurement characterized by equal intervals between values but without an absolute true zero point.

Ratio Scale

A scale of measurement characterized by equal intervals between values and an absolute true zero point.

Empirical Rule (Normal Curve)

States that for a normal distribution, approximately $68\%$ of scores fall within $\pm 1\,SD$, $95\%$ fall within $\pm 2\,SD$, and $99.7\%$ fall within $\pm 3\,SD$.

Esquirol

A French historical figure who emphasized language as a key criterion for determining intellectual level.

Séguin

A French historical figure who emphasized sensory and muscle training in early assessment and intervention.