A review of psych (1.0-90)

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An elegant package for applied psychometrics

It is a full-featured package for applied psychometrics, including exploratory factor analysis (with large support for choosing the number of factors), item cluster analysis (never found in any other R or Stata package so far), and correlation analysis.

Various functions allow to simulate structured data set (e.g. circumplex structure). Support for Item Response Theory or confirmatory approach is rather limited (except for the front-end to John Fox's sem package) but the user may rely on other packages (see the Psychometrics task view on CRAN).

It further includes facilities to handle responses to multi-items multi-scales questionnaire. Many reliability coefficients are available, together with tetrachoric and attenuated correlations. I found myself particularly attracted by all this stuff which is clearly a saving of R coding... Updates come on a regular basis and William Revelle is working on a textbook for the Springer Use R! series. The http://personality-project.org/r webpage contains a lot more of useful material; for the applied researcher, it is worth to have a look at this package and its accompanying on-line help now!