The ability to evaluate effects of factors on outcomes is increasingly important for a class of studies that control some but not all of the factors. Although important advances have been made in methods of analysis for such partially controlled studies,work on designs for such studies has been relatively limited. To help understand why, we review main designs that have been used for such partially controlled studies. Based on the review, we give two complementary reasons that explain the limited work on such designs, and suggest a new direction in this area.
Design of Experiments and Sample Surveys
Li, Fan and Frangakis, Constantine E. , "Designs in Partially Controlled Studies: Messages from a Review" (February 2005). Johns Hopkins University, Dept. of Biostatistics Working Papers. Working Paper 81.