This paper scrutinizes the increasing trend of using international large-scale assessment (ILSA) data for causal inferences in educational research, arguing that such inferences are often tenuous. We explore the complexities of causality within ILSAs, highlighting the methodological constraints that challenge the validity of causal claims derived…

Single-case experimental designs (SCEDs) have a long history in clinical and educational disciplines. One underdeveloped area in advancing SCED design and analysis is understanding the process of how internal validity threats and operational concerns are avoided or mitigated. Two strategies to ameliorate such issues in SCED involve replication and…

This guide offers a comprehensive handbook to scientific research methodology and experimental design, specifically for novice MA and PhD researchers in Education and Language Learning (TESOL/TEFL). It establishes scientific research as a systematic, objective inquiry focused on identifying cause-and-effect relationships through empirical data.…

As a research field geared toward understanding and improving learning, Learning Analytics (LA) must be able to provide empirical support for causal claims. However, as a highly applied field, tightly controlled randomized experiments are not always feasible nor desirable. Instead, researchers often rely on observational data, based on which they…

Treatment effect estimates from a "regression discontinuity design" (RDD) have high internal validity. However, the arguments that support the design apply to a subpopulation that is narrower and usually different from the population of substantive interest in evaluation research. The disconnect between RDD population and the…

Regression discontinuity design (RD) has been widely used to produce reliable causal estimates. Researchers have validated the accuracy of RD design using within study comparisons (Cook, Shadish & Wong, 2008; Cook & Steiner, 2010; Shadish et al, 2011). Within study comparisons examines the validity of a quasi-experiment by comparing its…

Although randomized studies have high internal validity, generalizability of the estimated causal effect from randomized clinical trials to real-world clinical or educational practice may be limited. We consider the implication of randomized assignment to treatment, as compared with choice of preferred treatment as it occurs in real-world…

Donald Campbell's approach to causal inference (D. T. Campbell, 1957; W. R. Shadish, T. D. Cook, & D. T. Campbell, 2002) is widely used in psychology and education, whereas Donald Rubin's causal model (P. W. Holland, 1986; D. B. Rubin, 1974, 2005) is widely used in economics, statistics, medicine, and public health. Campbell's approach focuses on…

This article compares Donald Campbell's and Donald Rubin's work on causal inference in field settings on issues of epistemology, theories of cause and effect, methodology, statistics, generalization, and terminology. The two approaches are quite different but compatible, differing mostly in matters of bandwidth versus fidelity. Campbell's work…

Experimental designs are distinguished as the best method to respond to questions involving causality. The purpose of the present paper is to explicate the logic of experimental design and why it is so vital to questions that demand causal conclusions. In addition, types of internal and external validity threats are discussed. To emphasize the…

"Theory as Method: Small Theories of Treatments," by Mark W. Lipsey, is one of the most influential and highly cited articles to appear in "New Directions for Evaluation." It articulated an approach in which methods for studying causation depend, in large part, on what is known about the theory underlying the program. Lipsey discussed the benefits…

This paper describes several common types of research studies in special education transition literature and the threats to their validity. It then describes how the evidential base may be broadened, how diverse sources of evidence can be combined to strengthen causal inferences, and the role of judgment within quasi-experimentation. The paper…

Abuses and misuses of statistics are frequent. This digest attempts to warn against these in three broad classes of pitfalls: sources of bias, errors of methodology, and misinterpretation of results. Sources of bias are conditions or circumstances that affect the external validity of statistical results. In order for a researcher to make…

Educational researchers are not engaged in discovering mechanistic universal truths sought by positivists or tidy prescriptions about what works. Instead, they provide guidelines and interpretive material to liberate the teacher's intelligence so that the teacher can use whatever ability he or she can achieve. (SLD)