Cronbach's alpha is the most frequently used measure to investigate the reliability of measurement instruments. Despite its frequent use, many warn for misinterpretations of alpha. These claims about regular misunderstandings, however, are not based on empirical data. To understand how common such beliefs are, we conducted a survey study to test…

There is extensive research on the benefits of making data-informed decisions, but research also contains evidence many educators incorrectly interpret student data. Meanwhile, the types of detailed labeling on over-the-counter medication have been shown to improve use of non-medication products, as well. However, data systems most educators use…

Experimental data are analysed statistically to allow researchers to draw conclusions from a limited set of measurements. The hard fact is that researchers can never be certain that measurements from a sample will exactly reflect the properties of the entire group of possible candidates available to be studied (although using a sample is often the…

Multiple regression and correlation (MRC) methods form a flexible family of statistical techniques that can address a wide variety of different types of research questions of interest to rehabilitation professionals. In this article, we review basic concepts and terms, with an emphasis on interpretation of findings relevant to research questions…

This document examined studies of the overjustification effect. Many studies examining the phenomenon were conducted during the 1970s; findings appeared to be accepted without qualification. It is unclear whether researchers conducted the studies with the proper methodologies and interpreted results correctly. Such factors included the type of…

Procedures used in Doctor of Education (Ed.D.) dissertations at the University of Alabama (Tuscaloosa) were studied. Focus was on identifying: (1) characteristics of the research designs used; (2) sources of the instruments used to collect data; (3) reports of reliability estimates and evidence of validity of the instruments; and (4) types of…

This study explored some practical issues for single-case researchers who rely on visual analysis of graphed data, but who also may consider supplemental use of promising statistical analysis techniques. The study sought to answer three major questions: (a) What is a typical range of effect sizes from these analytic techniques for data from…