Statistics — Page 7
Explore statistical methods, their assumptions, interpretation and limitations.
Research field
Method family
Ordinal Test-Retest Reliability
Ordinal test-retest reliability quantifies how consistently an ordinal measurement instrument — such as a Likert-scale questionnaire or a rating tool — ranks or scores the same participants across two separate administrations separated by a...
PCM / GPCM
The Partial Credit Model is an extension of the Rasch measurement framework designed for ordered polytomous items — items whose responses fall into more than two ordered categories, such as partial-credit tasks in performance assessment or...
Partial Least Squares Structural Equation Modeling
PLS-SEM is a variance-based approach to structural equation modeling developed by Herman Wold (1985) that estimates latent variable models by maximizing the variance explained in dependent variables. Unlike covariance-based SEM, PLS-SEM is...
Partisan Social Identity Scale
The Partisan Social Identity Scale treats party identification as a social identity in the sense of Henri Tajfel rather than as a running tally of policy agreement. Building on Steven Greene's social-identity approach and crystallized in Hu...
Political Cynicism Scale
The Political Cynicism Scale measures the disposition to hold politicians and politics in disrepute, viewing officeholders as dishonest, self-serving, and unresponsive. First operationalized by Agger, Goldstein, and Pearl in 1961, the const...
Political Ideology Scaling
Political ideology scaling estimates actors' positions on one or more latent ideological dimensions from their observed choices, most often legislators' roll-call votes, but also survey responses and donations. The dominant methods are Pool...
Polytomous Confirmatory Factor Analysis
Polytomous confirmatory factor analysis (CFA) tests a pre-specified factor structure when items have three or more ordered response categories (e.g., Likert scales). By working with polychoric correlations and robust estimators such as WLSM...
Polytomous Construct Validity
Polytomous construct validity refers to the evaluation of whether a scale composed of ordered, multi-category items (e.g., Likert or rating-scale items) genuinely measures the intended latent construct. It extends classical validity framewo...
Polytomous DIF
Polytomous differential item functioning detects whether a test or survey item with more than two ordered response categories (e.g., Likert-type scales, partial-credit items) functions differently across groups such as gender, ethnicity, or...
Polytomous EFA
Polytomous exploratory factor analysis extends standard EFA to ordered categorical (Likert-type) response data by replacing the Pearson correlation matrix with a polychoric correlation matrix. It recovers the latent continuous variable that...
Polytomous McDonald's omega
Polytomous McDonald's omega estimates the internal consistency reliability of a scale composed of ordinal (polytomous) items — such as Likert-type responses — by computing omega from a factor model fitted to the polychoric correlation matri...
Polytomous Measurement Invariance
Polytomous measurement invariance testing evaluates whether a scale with ordered categorical (polytomous) response options — such as Likert-type items — measures the same latent construct in the same way across two or more groups. It extend...
Polytomous Rasch Model
The Polytomous Rasch Model extends the dichotomous Rasch framework to ordered response scales with three or more categories, such as Likert items or partial-credit tasks. It estimates person ability and item difficulty on the same interval-...
Polytomous Reliability Analysis
Polytomous reliability analysis estimates the internal consistency or precision of measurement for scales composed of items with more than two ordered response categories, such as Likert-type, rating, or partial-credit items. It corrects a...
Polytomous item analysis
Polytomous item analysis examines the psychometric behavior of items that have more than two ordered response categories — such as Likert-type scales or partial-credit tasks. It evaluates each item's difficulty thresholds, discriminating po...
Polytomous scale development
Polytomous scale development is the systematic construction and validation of measurement instruments whose items have three or more ordered response categories — such as Likert-type, rating, or partial-credit items. It applies polytomous i...
Process Tracing
Process Tracing is a qualitative research method developed by George and Bennett (2005) for studying causal mechanisms and causal chains within individual cases. It involves examining the sequence of events and decision-making processes wit...
Pupillometry
Pupillometry is the measurement of changes in pupil size in response to cognitive, emotional, or perceptual stimuli. The pupil automatically dilates (mydriasis) during mental effort, emotional arousal, or approach-related states, and constr...
Q-Methodology
Q-Methodology is a mixed-methods approach that combines quantitative factor analysis with qualitative interpretation to identify distinct perspectives, viewpoints, or 'factors' shared by groups of people. Introduced by William Stephenson in...
Racial Resentment Scale
The Racial Resentment Scale, developed by Donald Kinder and Lynn Sanders in Divided by Color (1996), measures a modern, symbolic form of racial prejudice in which anti-Black affect is fused with the traditional American value of individuali...
Rasch Model
The Rasch model, introduced by Georg Rasch in 1960, is the simplest member of the Item Response Theory (IRT) family. It assigns a single difficulty parameter to each test item and places both item difficulties and person abilities on the sa...
Redundancy Analysis
Redundancy Analysis (RDA) is a multivariate technique developed by van den Wollenberg (1977) that combines multiple regression and principal component analysis. RDA finds linear combinations of predictor variables that best predict variatio...
Regulatory Focus Questionnaire
The Regulatory Focus Questionnaire (RFQ), developed by Higgins and colleagues in 2001, measures two independent motivational orientations derived from regulatory focus theory: a promotion focus concerned with growth, ideals, gains, and eage...
Repertory Grid
The Repertory Grid is a qualitative-quantitative method derived from Personal Construct Theory that elicits how individuals construe (interpret and evaluate) a domain of interest—people, concepts, events, or objects—through their own idiosy...