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psych (version 1.0-61)

Procedures for Personality, Psychometric, and Psychological Research

Description

A number of routines for personality, psychometrics and experimental psychology. Functions are primarily for scale construction using factor analysis, cluster analysis and reliability analysis, although others provide basic descriptive statistics. For more information, see the personality-project.org/r.

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Version

Install

install.packages('psych')

Monthly Downloads

178,796

Version

1.0-61

License

GPL version 2 or newer

Homepage

http://personality-project.org/r

Maintainer

William Revelle

Last Published

February 3rd, 2026

Functions in psych (1.0-61)

Intraclass Correlations (ICC1, ICC2, ICC3 from Shrout and Fleiss)

Cronbach alpha for a scale

Combine calls to head and tail

Find the probability of replication for an F, t, or r and estimate effect size

Item Response Theory estimate of theta (ability) using a Rasch (like) model

14 multiple choice IQ items

Find R = F F' + U2 is the basic factor model

create control code for ICLUST graphical output

Count number of pairwise cases for a data set with missing (NA) data.

Calculate skew or kurtosis for a vector, matrix, or data.frame

Function to form hierarchical cluster analysis of items

25 Personality items representing 5 factors

Score item composite scales and find Cronbach's alpha as well as associated statistics

Fisher r to z and z to r and confidence intervals

Form a super matrix from two sub matrices.

Plot factor/cluster loadings and assign items to clusters by their highest loading.

Basic descriptive statistics useful for psychometrics

Find the Standard deviation for a vector, matrix, or data.frame - do not return error if there are no cases

Simulate a congeneric data set

sim.hierarchical

Create a population or sample correlation matrix, perhaps with hierarchical structure.

Find the harmonic mean of a vector, matrix, or columns of a data.frame

Functions to simulate psychological/psychometric data

Principal Axis Factor Analysis

From a two by two table, find the Yule coefficients of association, convert to phi, or polychoric, recreate table the table to create the Yule coefficient.

Plot a scree test

Find the Squared Multiple Correlation (SMC) of each variable with the remaining variables in a matrix

Find the geometric mean of a vector or columns of a data.frame.

Principal components analysis

Plot x and y error bars

structure.graph

Draw (using Graphviz) a structural equation model specified by two measurement models and a structural model

Multiple histograms with density and normal fits on one page

score.multiple.choice

Score multiple choice items and provide basic test statistics

Draw an ICLUST graph using the Rgraphviz package

Print and summary functions for the psych class

Create a keys matrix for use by score.items or cluster.cor

SPLOM, histograms and correlations for a data matrix

Find dis-attenuated correlations given correlations and reliabilities

Convert base rates of two diagnoses and their comorbidity into phi, Yule, and tetrachorics

matrix.addition

A function to add two vectors or matrices

Convert Cartesian factor loadings into polar coordinates

Compare real and random VSS solutions

Two data sets showing a bifactor solution.

A package for personality, psychometric, and psychological research

3 Measures of ability: SATV, SATQ, ACT

Sort items by absolute size of cluster loadings

Create correlation matrices or data matrices with a particular measurement and structural model

Alternative estimates of test reliabiity

Functions for analysis of circadian or diurnal data

Find correlations of composite variables from a larger matrix

Convert eigen vectors and eigen values to the more normal (for psychologists) component loadings

polychor.matrix

Phi or Yule coefficient matrix to polychoric coefficient matrix

13 personality scales from the Eysenck Personality Inventory and Big 5 inventory

Plot data and 1 and 2 sigma correlation ellipses

cluster Fit: fit of the cluster model to a correlation matrix

Distances between 11 US cities

Galton's Mid parent child height data

Generate simulated data structures for circumplex or simple structure

Basic summary statistics by group

Function to convert scores to ``conventional " metrics

Apply four tests of circumplex versus simple structure

factor.congruence

Coefficient of factor congruence

Convert a cluster vector (from e.g., kmeans) to a keys matrix suitable for scoring item clusters.

ICLUST: Item Cluster Analysis -- Hierarchical cluster analysis using psychometric principles

Convert a phi coefficient to a polychoric correlation

Find the partial correlations for a set (x) of variables with set (y) removed.

Test the difference between (un)paired correlations

Plot means and confidence intervals

Find Cohen's kappa and weighted kappa coefficients for correlation of two raters

cortest.bartlett

Bartlett's test that a correlation matrix is an identity matrix

Calculate the omega estimate of factor saturation

shortcut for reading from the clipboard

Extract cluster definitions from factor loadings

A data.frame of the Galton (1888) height and cubit data set.

Plot means and confidence intervals for multiple groups

Create demo data for psychometrics

Graph hierarchical factor structures

Apply the Very Simple Structure and MAP criteria to determine the appropriate number of factors.

Galton's example of the relationship between height and 'cubit' or forearm length

Find the phi coefficient of correlation between two dichotomous variables

``Hand" rotate a factor loading matrix

Chi square tests of whether a single matrix is an identity matrix, or a pair of matrices are equal.

cluster.loadings

Find item by cluster correlations, corrected for overlap and reliability

create VSS like data

Multiple Regression from matrix input

factor.residuals

Tests of significance for correlations

simulation.circ

Simulations of circumplex and simple structure

Graph factor loading matrices

Scree plots of data or correlation matrix compared to random ``parallel" matrices

Apply the Schmid Leiman transformation to a correlation matrix

Paired comparison of preferences for 9 vegetables

Find polychoric correlations of item data

Score scales and find Cronbach's alpha as well as associated statistics

irt.item.diff.rasch

Simple function to estimate item difficulties using IRT concepts

Test the adequacy of simple choice, logistic, or Thurstonian scaling.

Find the trace of a square matrix

Convert a table with counts to a matrix or data.frame representing those counts.

Testing of functions in the psych package

Thurstone Case V scaling

How well does the factor model fit a correlation matrix. Part of the VSS package

Plotting functions for the psych package of class ``psych"

Find the interpolated sample median, quartiles, or specific quantiles for a vector, matrix, or data frame

Find the Winsorized scores or means for a vector, matrix, or data.frame