RESEARCH STANDARDS IN EARLY INTERVENTION - DEFINING, DESCRIBING, AND MEASURING THE INDEPENDENT VARIABLE

The purpose of this paper is to describe methodological issues related to the independent variable in early intervention research. Research in early intervention should be grounded in sound scientific principles which includes deriving the independent variable from relevant theories, defining the independent variable clearly and precisely, and measuring the implementation of the independent variable. Three standards related to the independent variable are proposed: (a) investigators should use theory to guide their research, including the selection of methods and the independent variable, and should describe those relationships in reports of their studies; (b) investigators should provide operational definitions of their independent variables, quantify these variables, and describe how they relate to theory; and (c) investigators should measure treatment fidelity (i.e., the extent to which the independent variable is implemented as planned). For each standard, three levels of documentation are proposed.