Logic is the systematic study of cogent reasoning. Reasoning emphasizes the process of drawing inferences (conclusions) from some initial information (premise). In standard logic, when the truth of the conclusions follows the premises, we refer to it as deduction. That…
External validity is about the generalizability of the results to different populations, settings, periods, treatment variables, and measurement variables. Then, threats to external validity are the conditions that limit this generalization of the results. Since external validity specifies conditions under…
Threats to internal validity are characteristics of research design that jeopardize our ability to interpret and make appropriate inferences. That is, it is an evaluation of the research design to provide causal inference. But to infer causality we must be…
We are very well aware of type I and type II errors in statistics. However, there is the error of the third kind or type III error that is more conceptual than type I and type II. It results from…
Empirical research is often conducted to establish evidence of a phenomenon or relationship, to examine and evaluate causal relationships, or to provide an explanation of how, why, and under what conditions a causal relationship exists. The purpose of the research…
In the previous post, we talked about measurement validity. But validity also relates to the ability of the research design to provide evidence of a cause-and-effect relationship between the independent and the dependent variable. This type of validity is known…
Validity in scientific research is arguably one of the most important properties of measurement as every aspect of research design can impact the validity of the research. Cook and Campbell (1979) defined it as “the best available approximation to the…
Consider if you were a photographer who has the perfect zoom lens and a great wide-angle lens. You can choose to photograph things in extreme detail or you can choose to photograph a big picture that provides a broader context.…
Reliability, fundamentally, concerns the extent to which a measure, an experiment, or test yields the same results on repeated trials. However, the measurement of any phenomenon invariably contains a certain amount of chance error. Even repeated measures of the same…
Reliability coefficients measure the consistency of a measurement scale. That is, they answer the question — how consistent is the scale or instrument when multiple observations are taken when the true score is unchanged? The reliability coefficient quantifies the precision…
