In paired experiments, participants are grouped into pairs with similar characteristics, and one observation from each pair is randomly assigned to treatment. The resulting treatment and control groups should be well-balanced; however, there may still be small chance imbalances. Building on work for completely randomized experiments, we propose a…

Initial learning can interfere with subsequent learning (proactive interference [PI]), but recent work indicates initial testing can reduce PI. Here, we tested 2 alternative hypotheses of this effect: Does testing reduce PI by constraining retrieval to the target list, or by facilitating a postretrieval monitoring process? Participants first…

The authors' data contain inter- and intra-class variations in experiments to which students in a principles of microeconomics course were exposed. These variations allowed the estimation of the effect on student achievement from the experimental treatment generally, as well as effects associated with participation in specific experiments. The…

An industrial-type distillation column, including appropriate pumps, heat exchangers, and automation, was used as a unit operations experiment to provide a link between classroom teaching and real-world applications. Students were presented with an open-ended experiment where they defined the testing parameters to solve a generalized problem. The…

The main result of an experiment is typically an estimate of the average treatment effect (ATE) and its standard error. In most experiments, the number of covariates that may be moderators is large. One way this issue is typically skirted is by interpreting the ATE as the average effect for "some" population. Cornfield and Tukey (1956)…

As a result of the use of random assignment to treatment, randomized experiments typically have high internal validity. However, units are very rarely randomly selected from a well-defined population of interest into an experiment; this results in low external validity. Under nonrandom sampling, this means that the estimate of the sample average…

Introduction: Star and Bowker describe the residual as what does not fit into a category system and as an inevitable byproduct of classification. In this project, we explore what happens when we attempt to give prominence to the residual instead of minimizing it. Methods: The three authors created three "transformations" of a small…

Recent research on the design of social experiments has highlighted the effects of different design choices on research findings. Since experiments rarely collect their samples using random selection, in order to address these external validity problems and design choices, recent research has focused on two areas. The first area is on methods for…

Research indicates that false memory is lower following visual than auditory study, potentially because visual information is more distinctive. In the present study we tested the extent to which retrieval orientation can cause a modality effect on memory accuracy. Participants studied unrelated words in different modalities, followed by criterial…

Classroom experiments in economics continue to increase in popularity. While early experiments were often hand-run in class, now computerized online experiments are also widely available. Using a quasiexperimental approach, the authors investigated whether any difference in student achievement (as measured by course scores and the "Test of…

To test the extent to which learners performing a simple keyboard passage would be affected by directing their focus of attention to different aspects of their movements, 16 music majors performed a brief keyboard passage under each of four focus conditions arranged in a counterbalanced design--a total of 64 experimental sessions. As they…

The conditions for serial search are described. A multiple target search methodology (Thornton & Gilden, 2007) is used to home in on the simplest target/distractor contrast that effectively mandates a serial scheduling of attentional resources. It is found that serial search is required when (a) targets and distractors are mirror twins, and…

The purpose of this study was to explore how high school social studies teachers made sense of curriculum work. The setting was a large, urban area in Texas with high percentages of students who were considered economically disadvantaged. The context of the study was important because these teachers were implementing revised standards and new…

Most modern research on the effects of feedback during learning has assumed that feedback is an error correction mechanism. Recent studies of feedback-timing effects have suggested that feedback might also strengthen initially correct responses. In an experiment involving cued recall of trivia facts, we directly tested several theories of…

Statistics is a critical tool for robustness analysis, measurement system error analysis, test data analysis, probabilistic risk assessment, and many other fields in the engineering world. Traditionally, however, statistics is not extensively used in undergraduate engineering technology (ET) programs, resulting in a major disconnect from industry…