The patient then waited through an extended period for healing. Then, in a surgery similar to those done to create vaginas for intersexed patients, surgeons constructed the patient's vagina by using skin grafts taken from her thighs or buttocks (Christine's vaginoplasty surgery was in 1954).
Experimental and quasi-experimental research designs. Ph.D. In an experimental design, subjects are randomly assigned to groups for different levels of treatment (or no treatment, i.e., the control group). In a quasi-experimental design, subjects are not randomly assigned to treatment; there is no randomization. Random assignments of subjects helps control for participant differences, one of the main sources of threats to internal validity of a research study.
In quasi-experimental designs, outcomes may only be measured at the end of the study (rather than at the beginning and end), there may not be a control group, or patients may be assigned to the control and treatment groups by methods other than randomization.n 1979, in their classic textbook Quasi-Experimentation: Design and Analysis Issues for Field Settings Cook and Campbell describe quasi-experimental designs and their limitations. That work is the basis for the following discussion.