This report presents a review of the statistical practices of 30 journals representative of the second language field. A review of 150 articles showed a number of prevalent statistical violations including incomplete reporting of reliability, validity, non-significant results, effect sizes, and assumption checks as well as making inferences from…

In experimental research, internal validity refers to what extent researchers can conclude that changes in dependent variable (i.e. outcome) are caused by manipulations in independent variable. The causal inference permits researchers to meaningfully interpret research results. This article discusses (a) internal validity threats in social and…

In this chapter, the authors discuss the issue of research design in conducting inquiry on college impact and demonstrate the importance of longitudinal pretest-posttest designs in maximizing the internal validity of findings. They begin by discussing the strengths and weaknesses of different types of research design in the college impact…

Measurement of affective states in everyday life is of fundamental importance in many types of quality of life, health, and psychological research. Ecological momentary assessment (EMA) is the recognized method of choice, but the respondent burden can be high. The day reconstruction method (DRM) was developed by Kahneman and colleagues ("Science,"…

Nursing intervention studies are much needed. However, careful delineation of independent variables and protocols is necessary to ensure the validity of results. (SK)

Ridge regression offers advantages over ordinary least squares estimation when a validity shrinkage criterion is considered. Comparisons of cross-validated multiple correlations indicate that ridge estimation is superior when the predictors are multicollinear, the number of predictors is large relative to sample size, and the population multiple…

Compares approaches to modeling ordinal outcome variables, including assumptions, interpretations, and limitations. Explores how the multiple regression approach with ordinal level data can compromise the understanding of the effects of the independent variables and of the ordinal level response. Provides applications with data from a multisite…

It is generally believed that the correction formula will yield exact correlational values only when the regression of z on x is both linear and homoscedastic. The formula is shown to hold for nonlinear heteroscedastic relationships. A simple sufficient condition for formula validity and estimation predictions is demonstrated in a numerical…

Documenting treatment integrity is an important issue in research and practice in any discipline concerned with prevention and intervention. However, consensus concerning the dimensions of treatment integrity and how they should be measured has yet to emerge. Advances from three areas in which significant treatment integrity work has taken…

The concept of treatment integrity cuts across a diversity of fields involved with providing treatments or interventions to individuals. In medical treatments, the concept of "treatment compliance" or "treatment adherence" is an important and problematic issue. In the field of nutrition, the concept of "dietary adherence" is important for…

It has been increasingly realized that (1) multivariate methods are essential in most quantitative studies (Fish, 1988; Thompson, 1992), and (2) all conventional parametric analytic methods are correlational and invoke least squares weights (e.g., the beta weights in regression) (Knapp, 1978; Thompson, 1991). The present paper reviews one very…

Social facilitation can be defined as the effect of an audience or coactors on performance. Research on social facilitation effects has produced some contradictory and confusing findings. Some studies have found that the presence of others enhances performance; other studies have found that the presence of an audience or coactors impairs…

The authors question Burgoon's assumption that the acquisition of grades and the achievement of course goals are highly positively correlated. The major criticisms of Burgoon's study concern use of grades as measurements of success and the nature of the experimental population. The use of grades is criticized on the grounds that disparity existed…

The central thesis of this article is that the process of eliminating validity threats depends fundamentally on no-difference findings, a fact that has not been made explicit by researchers. The implications of this neglect are explored using examples from a number of different substantive areas such as psychology, health, and medicine.…

Studies published since 1965 on the relationship between classroom behavior and academic achievement are reviewed. Criteria are established for selecting the studies, the research is assessed, and recommendations for future research are made. (MH)