psych v1.3.2


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by William Revelle

Procedures for Psychological, Psychometric, and Personality Research

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. Item Response Theory is done using factor analysis of tetrachoric and polychoric correlations. Functions for simulating particular item and test structures are included. Several functions serve as a useful front end for structural equation modeling. Graphical displays of path diagrams, factor analysis and structural equation models are created using basic graphics. Some of the functions are written to support a book on psychometrics as well as publications in personality research. For more information, see the webpage.

Functions in psych

Name Description
ICC Intraclass Correlations (ICC1, ICC2, ICC3 from Shrout and Fleiss)
alpha Find two estimates of reliability: Cronbach's alpha and Guttman's Lambda 6.
SD Find the Standard deviation for a vector, matrix, or data.frame - do not return error if there are no cases
ICLUST.sort Sort items by absolute size of cluster loadings
cushny A data set from Cushny and Peebles (1905) on the effect of three drugs on hours of sleep, used by Student (1908)
Harman Two data sets from Harman (1967). 9 cognitive variables from Holzinger and 8 emotional variables from Burt
cluster.cor Find correlations of composite variables from a larger matrix
epi.bfi 13 personality scales from the Eysenck Personality Inventory and Big 5 inventory
diagram Helper functions for drawing path model diagrams
ICLUST.cluster Function to form hierarchical cluster analysis of items
block.random Create a block randomized structure for n independent variables
fisherz Fisher r to z and z to r and confidence intervals
error.bars Plot means and confidence intervals
bfi 25 Personality items representing 5 factors
Schmid 12 variables created by Schmid and Leiman to show the Schmid-Leiman Transformation
biplot.psych Draw biplots of factor or component scores by factor or component loadings
blot Bond's Logical Operations Test -- BLOT
describe Basic descriptive statistics useful for psychometrics
ICLUST.rgraph Draw an ICLUST graph using the Rgraphviz package
lowerUpper Combine two square matrices to have a lower off diagonal for one, upper off diagonal for the other
burt 11 emotional variables from Burt (1915)
cluster2keys Convert a cluster vector (from e.g., kmeans) to a keys matrix suitable for scoring item clusters.
cor2dist Convert correlations to distances (necessary to do multidimensional scaling of correlation data)
VSS.scree Plot the successive eigen values for a scree test
cortest.bartlett Bartlett's test that a correlation matrix is an identity matrix
eigen.loadings Convert eigen vectors and eigen values to the more normal (for psychologists) component loadings Plot means and confidence intervals for multiple groups
VSS.parallel Compare real and random VSS solutions
cluster.loadings Find item by cluster correlations, corrected for overlap and reliability
partial.r Find the partial correlations for a set (x) of variables with set (y) removed.
fa.diagram Graph factor loading matrices cluster Fit: fit of the cluster model to a correlation matrix
fa.sort Sort factor analysis or principal components analysis loadings
Harman.8 Correlations of eight physical variables (from Harman, 1966)
sim.structure Create correlation matrices or data matrices with a particular measurement and structural model
df2latex Convert a data frame, correlation matrix, or factor analysis output to a LaTeX table
plot.psych Plotting functions for the psych package of class ``psych"
corr.test Find the correlations, sample sizes, and probability values between elements of a matrix or data.frame.
heights A data.frame of the Galton (1888) height and cubit data set.
describeBy Basic summary statistics by group
harmonic.mean Find the harmonic mean of a vector, matrix, or columns of a data.frame
Harman.5 5 socio-economic variables from Harman (1967)
Yule 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.
bock Bock and Liberman (1970) data set of 1000 observations of the LSAT
cosinor Functions for analysis of circadian or diurnal data
cities Distances between 11 US cities
Promax Perform bifactor, promax or targeted rotations and return the inter factor angles.
cluster.plot Plot factor/cluster loadings and assign items to clusters by their highest loading.
galton Galton's Mid parent child height data
kaiser Apply the Kaiser normalization when rotating factors
cortest.mat Chi square tests of whether a single matrix is an identity matrix, or a pair of matrices are equal.
ICLUST.graph create control code for ICLUST graphical output
score.items Score item composite scales and find Cronbach's alpha, Guttman lambda 6 and item whole correlations
geometric.mean Find the geometric mean of a vector or columns of a data.frame.
ellipses Plot data and 1 and 2 sigma correlation ellipses
factor.rotate ``Hand" rotate a factor loading matrix
affect Two data sets of affect and arousal scores as a function of personality and movie conditions
scrub A utility for basic data cleaning and recoding. Changes values outside of minimum and maximum limits to NA.
VSS.plot Plot VSS fits
table2matrix Convert a table with counts to a matrix or data.frame representing those counts.
cor.plot Create an image plot for a correlation or factor matrix
polar Convert Cartesian factor loadings into polar coordinates
income US family income from US census 2008
count.pairwise Count number of pairwise cases for a data set with missing (NA) data.
Tucker 9 Cognitive variables discussed by Tucker and Lewis (1973)
Dwyer 8 cognitive variables used by Dwyer for an example.
factor2cluster Extract cluster definitions from factor loadings
parcels Find miniscales (parcels) of size 2 or 3 from a set of items
scatter.hist Draw a scatter plot with associated X and Y histograms, densitie and correlation
mat.sort Sort the elements of a correlation matrix to reflect factor loadings
headTail Combine calls to head and tail
factor.stats Find various goodness of fit statistics for factor analysis and principal components
cor.smooth Smooth a non-positive definite correlation matrix to make it positive definite
error.crosses Plot x and y error bars
cor.wt The sample size weighted correlation may be used in correlating aggregated data
circ.tests Apply four tests of circumplex versus simple structure
cta Simulate the C(ues) T(endency) A(ction) model of motivation
mssd Find von Neuman's Mean Square of Successive Differences
score.alpha Score scales and find Cronbach's alpha as well as associated statistics
principal Principal components analysis (PCA)
comorbidity Convert base rates of two diagnoses and their comorbidity into phi, Yule, and tetrachorics
draw.tetra Draw a correlation ellipse and two normal curves to demonstrate tetrachoric correlation
Harman.political Eight political variables used by Harman (1967) as example 8.17
cubits Galton's example of the relationship between height and 'cubit' or forearm length
Bechtoldt Seven data sets showing a bifactor solution.
structure.list Create factor model matrices from an input list
dummy.code Create dummy coded variables
fa Exploratory Factor analysis using MinRes (minimum residual) as well as EFA by Principal Axis, Weighted Least Squares or Maximum Likelihood
VSS Apply the Very Simple Structure and MAP criteria to determine the appropriate number of factors.
iclust iclust: Item Cluster Analysis -- Hierarchical cluster analysis using psychometric principles
errorCircles Two way plots of means, error bars, and sample sizes
sat.act 3 Measures of ability: SATV, SATQ, ACT
interp.median Find the interpolated sample median, quartiles, or specific quantiles for a vector, matrix, or data frame
mixed.cor Find correlations for mixtures of continuous, polytomous, and dichotomous variables
00.psych A package for personality, psychometric, and psychological research
score.irt Find Item Response Theory (IRT) based scores for dichotomous or polytomous items
thurstone Thurstone Case V scaling
omega.graph Graph hierarchical factor structures
matrix.addition A function to add two vectors or matrices
reverse.code Reverse the coding of selected items prior to scale analysis
r.test Tests of significance for correlations
factor.congruence Coefficient of factor congruence
irt.responses Plot probability of multiple choice responses as a function of a latent trait
pairs.panels SPLOM, histograms and correlations for a data matrix
read.clipboard shortcut for reading from the clipboard
simulation.circ Simulations of circumplex and simple structure
iqitems 16 multiple choice IQ items
psych.misc Miscellaneous helper functions for the psych package
winsor Find the Winsorized scores, means, sds or variances for a vector, matrix, or data.frame
phi Find the phi coefficient of correlation between two dichotomous variables
residuals.psych Extract residuals from various psych objects
mardia Calculate univariate or multivariate (Mardia's test) skew and kurtosis for a vector, matrix, or data.frame
sim Functions to simulate psychological/psychometric data.
statsBy Find statistics (including correlations) within and between groups for basic multilevel analyses
p.rep Find the probability of replication for an F, t, or r and estimate effect size
fa.parallel Scree plots of data or correlation matrix compared to random ``parallel" matrices
rescale Function to convert scores to ``conventional " metrics
factor.residuals R* = R- F F'
spider Make "radar" or "spider" plots.
irt.item.diff.rasch Simple function to estimate item difficulties using IRT concepts
sim.hierarchical Create a population or sample correlation matrix, perhaps with hierarchical structure.
iclust.diagram Draw an ICLUST hierarchical cluster structure diagram
smc Find the Squared Multiple Correlation (SMC) of each variable with the remaining variables in a matrix
fa.extension Apply Dwyer's factor extension to find factor loadings for extended variables
tr Find the trace of a square matrix
vegetables Paired comparison of preferences for 9 vegetables
bi.bars Draw pairs of bargraphs based on two groups
structure.diagram Draw a structural equation model specified by two measurement models and a structural model
predict.psych Prediction function for factor analysis or principal components
paired.r Test the difference between (un)paired correlations
withinBetween An example of the distinction between within group and between group correlations
irt.1p Item Response Theory estimate of theta (ability) using a Rasch (like) model
factor.model Find R = F F' + U2 is the basic factor model How well does the factor model fit a correlation matrix. Part of the VSS package
multi.hist Multiple histograms with density and normal fits on one page
msq 75 mood items from the Motivational State Questionnaire for 3896 participants
phi.demo A simple demonstration of the Pearson, phi, and polychoric corelation
factor.scores Various ways to estimate factor scores for the factor analysis model
logistic Logistic transform from x to p and logit transform from p to x
score.multiple.choice Score multiple choice items and provide basic test statistics
sim.anova Simulate a 3 way balanced ANOVA or linear model, with or without repeated measures.
scaling.fits Test the adequacy of simple choice, logistic, or Thurstonian scaling.
tetrachoric Tetrachoric, polychoric, biserial and polyserial correlations from various types of input
correct.cor Find dis-attenuated correlations given correlations and reliabilities
set.cor Set Correlation and Multiple Regression from matrix or raw input
rangeCorrection Correct correlations for restriction of range. (Thorndike Case 2)
test.psych Testing of functions in the psych package
sim.VSS create VSS like data
peas Galton`s Peas
polychor.matrix Phi or Yule coefficient matrix to polychoric coefficient matrix
omega Calculate McDonald's omega estimates of general and total factor saturation
sim.item Generate simulated data structures for circumplex or simple structure
superMatrix Form a super matrix from two sub matrices.
sim.multilevel Simulate multilevel data with specified within group and between group correlations
glb.algebraic Find the greatest lower bound to reliability.
cohen.kappa Find Cohen's kappa and weighted kappa coefficients for correlation of two raters
make.keys Create a keys matrix for use by score.items or cluster.cor
phi2poly Convert a phi coefficient to a polychoric correlation
neo NEO correlation matrix from the NEO_PI_R manual
KMO Find the Kaiser, Meyer, Olkin Measure of Sampling Adequacy
Gorsuch Example data set from Gorsuch (1997) for an example factor extension.
irt.fa Item Response Analysis by Exploratory Factor Analysis of tetrachoric/polychoric correlations
guttman Alternative estimates of test reliabiity
print.psych Print and summary functions for the psych class
sim.congeneric Simulate a congeneric data set
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Date 2013-02-28
License GPL (>= 2)
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Packaged 2013-02-26 16:13:45 UTC; revelle
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Date/Publication 2013-02-26 17:33:22

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