Statistics — Page 3
Explore statistical methods, their assumptions, interpretation and limitations.
Research field
Method family
Longitudinal Discriminant Validity
Longitudinal discriminant validity tests whether a psychological construct measured at two or more time points is empirically distinct across occasions — ensuring that the same construct does not collapse into a single undifferentiated mass...
Longitudinal Generalizability Theory
Longitudinal generalizability theory extends classical G-theory to repeated-measures and longitudinal designs, decomposing score variance across persons, measurement occasions, raters, and items simultaneously. It quantifies how reliably sc...
Longitudinal IRT
Longitudinal IRT extends classical item response theory to data collected at multiple time points, allowing researchers to model both the initial latent trait level and its change over time. It is used in educational assessment, clinical tr...
Longitudinal McDonald's omega
Longitudinal McDonald's omega estimates scale reliability separately at each measurement occasion in a panel or repeated-measures study. By fitting a confirmatory factor model at each wave, it tracks how consistently a set of items measures...
Longitudinal Measurement Invariance
Longitudinal measurement invariance testing determines whether a psychological scale measures the same construct in the same way across two or more time points. It is a prerequisite for interpreting mean-level change scores in panel and rep...
Longitudinal Nomological Validity
Longitudinal nomological validity evaluates whether a construct's theoretically predicted relationships with other constructs hold consistently across multiple measurement occasions. It extends the nomological network framework of Cronbach...
Longitudinal Reliability Analysis
Longitudinal reliability analysis evaluates the consistency and stability of measurement instruments across two or more time points. It extends classical reliability concepts — internal consistency, test-retest stability, and measurement pr...
Longitudinal Test-Retest Reliability
Longitudinal test-retest reliability quantifies how consistently a scale or measure performs across two or more time points in a longitudinal study. It extends the classic test-retest paradigm by accounting for planned, often substantive, t...
Longitudinal content validity
Longitudinal content validity evaluates whether the items of a measure adequately and consistently represent the intended content domain not only at a single point in time but across repeated administrations. It ensures that the conceptual...
Longitudinal convergent validity
Longitudinal convergent validity evaluates whether a scale's indicators correlate with theoretically related constructs not just at a single time point but consistently across repeated measurement occasions. It extends standard convergent v...
Longitudinal scale development
Longitudinal scale development is the systematic process of constructing and validating a measurement instrument using data collected at multiple time points. It extends classical scale development by additionally testing whether the scale...
MCP Penalized Regression
MCP (Minimax Concave Penalty) is a variable selection method developed by Zhang (2010) that uses a concave penalty function for automated feature selection. Like SCAD, MCP addresses bias in lasso by avoiding shrinkage of large coefficients,...
McDonald's Omega
McDonald's hierarchical omega (ωh) is a coefficient derived from a bifactor confirmatory factor model that quantifies what proportion of total-score variance is attributable to a single general factor rather than to group-specific factors o...
McDonald's Omega
McDonald's omega is a factor-analysis-based reliability coefficient introduced by Roderick P. McDonald (1999) that quantifies the internal consistency of a composite score without requiring the restrictive assumption that all items contribu...
Measurement Invariance
Measurement invariance testing is a sequence of nested confirmatory factor analysis (CFA) models that examines whether a psychological scale measures the same latent construct in the same way across distinct groups or time points. Systemati...
Multi-group Differential Item Functioning
Multi-group differential item functioning examines whether test or scale items function equivalently across three or more distinct groups — such as gender, ethnicity, or country — after matching respondents on the underlying trait being mea...
Multi-group Generalizability Theory
Multi-group generalizability theory (MG G-theory) extends classical generalizability theory to estimate and compare variance components — attributable to persons, items, raters, occasions, and their interactions — simultaneously across two...
Multi-group McDonald's omega
Multi-group McDonald's omega estimates and compares the reliability of a scale across two or more distinct groups. Rooted in confirmatory factor analysis, it uses the factor loadings and unique variances from each group's measurement model...
Multi-group Rasch model
The multi-group Rasch model fits the one-parameter logistic item response model simultaneously across two or more distinct groups, testing whether item difficulty parameters are invariant across groups. It is the primary psychometric tool f...
Multi-group Reliability Analysis
Multi-group reliability analysis estimates internal consistency or stability coefficients separately within each group and then formally compares them to determine whether a scale functions with equal precision across populations. It is a f...
Multi-group content validity
Multi-group content validity extends the standard content validity index (CVI) procedure by computing and comparing item- and scale-level validity indices across two or more distinct expert panels or subgroups. It ensures that a scale's ite...
Multi-group convergent validity
Multi-group convergent validity examines whether items purported to measure the same latent construct relate strongly to that construct consistently across distinct subgroups such as demographic categories, cultures, or experimental conditi...
Multi-group discriminant validity
Multi-group discriminant validity assessment tests whether constructs measured by a scale are empirically distinct not just in one sample but consistently across two or more groups (e.g., cultures, genders, age cohorts). It extends standard...
Multi-group item analysis
Multi-group item analysis computes classical item statistics — difficulty, discrimination, and corrected item-total correlations — separately for each subgroup in a sample and then compares those statistics across groups. It is a standard d...