Provides tools for analyzing, teaching, and studying the Solomon four-group experimental design. The package includes the historical Tests A-I workflow, unified generalized linear models with robust covariance estimation, stratified randomization inference, Solomon-specific full-information maximum likelihood, and observed- and latent-variable structural equation models.
Details
The package distinguishes historically important procedures from contemporary recommendations and emphasizes explicit Solomon-specific estimands, structural pretest missingness, reproducible diagnostics, and modern inference.
Key historical references include Huck & Sandler (1973), Braver & Braver (1988), the Sawilowsky and Markman methodological exchanges, and van Engelenburg (1999).
References
Solomon, R. L. (1949). An extension of control group design. Psychological Bulletin, 46(2), 137-150.
Campbell, D. T., & Stanley, J. C. (1963). Experimental and quasi-experimental designs for research. Rand McNally.
Huck, S. W., & Sandler, H. M. (1973). A note on the Solomon 4-group design: Appropriate statistical analyses. The Journal of Experimental Education, 42(2), 54-55.
Braver, M. W., & Braver, S. L. (1988). Statistical treatment of the Solomon four-group design: A meta-analytic approach. Psychological Bulletin, 104(1), 150-154.
Sawilowsky, S. S., Kelley, D. L., Blair, R. C., & Markman, B. S. (1994). Meta-analysis and the Solomon four-group design. The Journal of Experimental Education, 62(4), 361-376.
van Engelenburg, G. (1999). Statistical analysis for the Solomon four-group design (Research Report 99-06). University of Twente.