leunbachR: Leunbach test equating using R

This package aims to implement the Leunbach test equating procedures in the software DIGRAM, created by Svend Kreiner and Karl Bang Christensen. Both direct and indirect equating is implemented.

The equating procedure is described in detail in the Additional file 1 related to this article: Adroher, N. D., Kreiner, S., Young, C., Mills, R., & Tennant, A. (2019). Test equating sleep scales: Applying the Leunbach’s model. BMC Medical Research Methodology, 19(1), 141. https://doi.org/10.1186/s12874-019-0768-y

Installation

You can install the package from CRAN:

install.packages('leunbachR')

If you want to use parallel processing, which speeds up the bootstrap procedure considerably, you should also install the package mirai.

There is an intro article under the heading Articles at the top of this page, showing the basic functionality.

Credits

• This work was funded by the Swedish Defence University and the Swedish Defence Conscription and Assessment Agency.
• Svend Kreiner kindly shared the source code for the DIGRAM test equating procedure and provided helpful information and guidance.
• Claude Opus 4.5 produced most of the code, based on the DIGRAM pascal code.
• Jeanette Melin and Henrik Nordström at the Swedish Defence University helped with testing and provided useful feedback.

Author

Magnus Johansson is a licensed psychologist with a PhD in behavior analysis. He works as a research specialist at Karolinska Institutet, Department of Clinical Neuroscience, Center for Psychiatry Research.

• ORCID: 0000-0003-1669-592X
• Bluesky: @pgmj.bsky.social