Background/Context: Principles of evidential reasoning have often been discussed in the context of educational and psychological measurement with respect to construct validity and validity arguments. More recently, Mislevy proposed the metaphor of assessment as an evidentiary argument about students' learning and abilities given their…

In true experiments in which sample material can be randomly assigned to treatment conditions, most researchers presume that the condition of equal sample sizes is statistically desirable. When one or more a priori contrasts can be identified which represent a few overriding experimental concerns, however, allocating sample material unequally will…

Presents 17 research paradigms students might employ for doctoral dissertations on instructional design, makes suggestions for students evaluating the literature and developing a conceptual framework for research, and summarizes dissertations developed by University of Florida doctoral students, classifying them into three research paradigms which…

GREATER UNDERSTANDING OF INFERENTIAL STATISTICAL METHODS AND EXPERIMENTAL DESIGN WOULD ENABLE LANGUAGE TEACHERS TO INTERPRET OBJECTIVELY AVAILABLE RESEARCH REPORTS AND HOPEFULLY WOULD ENCOURAGE MORE EXPERIMENTATION. TO UNDERSTAND THE EXPERIMENTAL PROCESS, EDUCATORS MUST REALIZE THAT ANY EXPERIMENT IS AS SUCCESSFUL AS THE EXPERIMENTER IS IN…

The state of the art in observational studies is discussed, with emphasis on explanatory research--studies of program effectiveness in which an attempt is made to explain the reasons for the results as well as describing the results. In addition to the collection of data and presentation of statistical facts, the explanatory study involves the…

Statistical methods for program evaluation with nonexperimental data are reviewed with emphasis on circumstances in which nonexperimental data are valid. Three solutions are proposed for problems of selection bias, and implications for evaluation design and data collection and analysis are discussed. (SLD)