What is MBESS?

MBESS (pronounced em-bes) is an Open Source R Package that provides various advanced and nonstandard methods that are not easily implemented elsewhere, especially with regards to effect sizes, confidence intervals for effect sizes, and sample size planning. For those not familiar with R, R is a powerful program for statistical computing and graphics and is Freely available for (essentially) all operating systems. Originally, MBESS stood for “Methods for the Behavioral, Educational, and Social Sciences,” but at this point MBESS contains methods applicable and used in a wide variety of fields and is functionally an orphan acronym, in the sense that what was an acronym is now literally its name.

The Goal of MBESS-General

The goal of MBESS is to provide substantive and quantitative researchers with an R package that contains useful functions for nonstandard techniques when designing and analyzing research studies.

The Goal of MBESS-Specific

The long term goal of MBESS is for it to contain a relatively complete set of functions to compute a wide variety of unstandardized and standardized effect sizes, confidence intervals for those effect sizes, and to plan sample size from the power analytic and accuracy in parameter estimation approaches.

Strengths of MBESS

A particular of strength MBESS is its easy implementation of confidence interval for noncentrality parameters from the noncentral t, noncentral F, and noncentral chi-square distributions. These are then called upon by functions for confidence intervals for standardized effect sizes so that simple commands can be used.

Contribute

Anyone is welcome to make contributes to MBESS. Contributions can be as simple as submitting ideas for functions that you would like to see included in the MBESS package (feel free to email me with any ideas), by pointing out bugs or typos (such contributions will be noted in the Acknowledgements file), or by submitting functions that can be included in the package (of course, the author of the function will be given in the help-files for the contributed functions).

Licensing Information

The MBESS package is Open Source software that follows the guidelines set forth by the Free Software Foundation's GNU General Public License. Thus, the MBESS software (i.e., code) is freely available to anyone and can be freely modified by anyone (although, if the MBESS package is modified its name must be changed).

Getting and Using MBESS

The MBESS source code, Mac and Windows binaries, and help files are available on the Comprehensive R Archival Network's MBESS page. The easiest way to get MBESS is actually to use the "install package(s)" facility within R.

Getting Help with MBESS

The MBESS Help files are available here.

History of MBESS

The first public release version (0.0.1) of MBESS was May 6, 2006. MBESS was peer reviewed in Kelley (2007a, Behavior Research Methods) and Kelley (2007b, Journal of Statistical Software). With MBESS 3.0, my graduate student Keke (Brian) Lai became the second author of the package. Version 1.0 was released in December, 2007, Version 2.0 was released in November, 2008, and Version 3.0 was released in May, 2010. Please site the above noted papers as well as MBESS itself when MBESS is used within your research.