Post-instrument covariates are often included as controls in instrumental variable (IV) analyses to address a violation of the exclusion restriction. However, we show that such analyses are subject to biases unless strong assumptions hold. Using linear constant-effects models, we present asymptotic bias formulas for three estimators (with and…

It is common to include multiple dependent variables (DVs) in single-case experimental design (SCED) meta-analyses. However, statistical issues associated with multiple DVs in the multilevel modeling approach (i.e., possible dependency of error, heterogeneous treatment effects, and heterogeneous error structures) have not been fully investigated.…

In this paper, I extend the concept of observer effect into the realm of country-level secondary data analysis. When analyzing what appear to be the same secondary data using the same methods, macro-comparative researchers arrive at different results. I argue that this is a product of idiosyncratic variation directly or indirectly produced by the…

The rationale behind analysis of variance (including analysis of covariance and multiple analyses of variance and covariance) methods is reviewed, and unplanned and planned methods of evaluating differences between means are briefly described. Two advantages of using planned or a priori tests over unplanned or post hoc tests are presented. In…

Two techniques for determining a straight line fit to data are compared. This article reviews two simple techniques for fitting a straight line to a set of data, namely the method of averages and the method of least squares. These methods are compared by showing the results of a simple analysis, together with a number of tests based on randomized…

This report examines the difference in approaches between sociologists and psychologists when using multiple regression techniques in the analysis of behavioral data. Psychologists and sociologists are often divided in their orientation toward regression techniques, and this division could be a substantial and unfortunate barrier to communication…

This study compared 4,594 student responses from three different surveys of incoming students at the University of South Florida (USF) with data from Florida's State University System (SUS) admissions files to determine what proportion of error occurs in the survey responses. Specifically, the study investigated the amount of measurement error in…

One of the consistent findings of educational research studies is the effect of the students' family socio-economic background on their learning achievement. Consequently, international comparative studies emphasis the role of socio-economic background for determining learning outcomes. In particular, PISA results have been used to describe how…