The methodological parameters of evaluative research studies help to identify a conceptualization of the phenomenon under investigation. Holistic critiques that identify the conceptual models under which the research was conducted shed light on the validity of the disparate inferences made from a number of studies of schools and school effectiveness. This paper attempts such a critique of studies of school effectiveness in general, and the 1966 "Equality of Educational Opportunity Survey" by Coleman and others in particular. A table presents a brief overview of three studies of school effectiveness. Differences in the methodological parameters (data analysis strategy, stratification levels, level of data aggregation, and selection of independent and dependent variables) and the impact of these differences on conclusions about school effectiveness are identified and discussed. It is important that discussion of the methodological parameters characterizing varied research studies be put in a more general, conceptual framework, so that the model of schooling being examined by different researchers can be identified and critiqued. (Author/MLF)