Calculating Effect Sizes Using Survey Data
Liu, J. (2006, August). Calculating Effect Sizes Using Survey Data. Presented at Joint Statistical Meetings, Seattle, WA.
Effect Sizes are widely used in comparative studies to measure the impact of an intervention over the control. Although the definition of the Effect Size is well known and generally accepted, its estimation is less so. Furthermore, when data is collected from complex surveys, where clustering and stratification are common, it is not clear how the Effect Size should be calculated. We present a formula for calculating Effect Sizes that takes into consideration of the survey design features and is design consistent. We use simulations to examine its properties against other alternatives.