User manual and help files
- An introduction (pdf) to the psych package
- Using psych as a front end for sem (pdf) to the psych package
- Install R and psych on your computer.
- Use psych in order to find omega
- Score a set of items to use psych in order to find composite scores
- Factor analyze a data set
Short Course lecture notes
These are clickable pdf lecture notes
R is a very powerful open source system for statistical computation and graphics. It consists of a language plus a run-time environment with graphics, a debugger, access to certain system functions, and the ability to run programs stored in script files. Base R is a foundation upon which more than 4000 "packages" have been built. It is the use of these packages that makes R such a powerful tool for research.
The psych package has been developed at the Personality, Motivation and Cognition laboratory in the Department of Psychology at Northwestern University since 2005 to include functions most useful for personality, psychometric, and psychological research. The package is also meant to supplement a text on Psychometric Theory, a draft of which is available on line.
The development of the psych package was done in conjunction with the development of the Synthetic Aperture Personality Assessment (SAPA) project and is a core part of the International Cognitive Ability Resource (ICAR) project. The SAPA project includes a personality test that uses a massively missing at random strategy to measure dimensions of temperament, ability, and interests.
To start using the psych package, it is, of course, necessary to install R and the psych package. Then one should read the overview vignette about psych and work through those examples. There are several short courses demonstrating R as used for psychology. These are large files. Alternatively, the R guide might provide a good start.