What is Overmatching in a study?

Overmatching, sometimes referred to as overmatching bias, occurs when matching is done incorrectly or unnecessarily leading to reduced efficiency and biased results. Overmatching generally affects case-control studies. Effects of Overmatching. Loss of Statistical Efficiency.

What is an example of Overmatching?

For example, a researcher investigating a new drug treatment for cancer might create two groups whose members are of the same age and sex, administering the drug to one group and a placebo to the other group.

What is an example of Overmatching bias?

Overmatching thus causes statistical bias. For example, matching the control group by gestation length and/or the number of multiple births when estimating perinatal mortality and birthweight after in vitro fertilization (IVF) is overmatching, since IVF itself increases the risk of premature birth and multiple birth.

What is Overmatching in psychology?

overmatching. A deviation from matching in which the proportion of responses on the richer schedule versus poorer schedule is more different than would be predicted by matching. self-control. With respect to choice between two rewards, preference for a larger later reward over a smaller sooner reward.

What is Undermatching in psychology?

Undermatching can happen if subjects too often switch between the two response options, a tendency that may be strengthened by reinforcers that happen to occur just after a subject switches.

What is an example of information bias?

An example of information bias is believing that the more information that can be acquired to make a decision, the better, even if that extra information is irrelevant for the decision.

What is exclusion bias?

Exclusion bias: Collective term covering the various potential biases that can result from the post-randomization exclusion of patients from a trial and subsequent analyses. This may also be referred to as attrition bias.

What is the Generalised matching law?

in behavioral studies, a formula in the form of a power function (y = axb ) that describes the choice between two alternatives in terms of the ratio (y) of rates of occurrence of (or time spent in) each alternative and the ratio (x) of the rates of reinforcement of the two alternatives.

What is Undermatching and Overmatching?

Undermatching and overmatching are derived from two separate, and opposing, tendencies. The first is a tendency to allocate a certain proportion of response bursts randomly to a response alternative without regard for the rate of reinforcement it provides, others being allocated according to the simple matching law.

What is the Premack principle and how can it be used in your life to improve performance of behaviors?

The Premack Principle, also called the relativity theory of reinforcement, and the differential-probability hypothesis, states that a more desirable activity (e.g. such as eating chocolate) can be used to reinforce a less desirable one (such as writing an essay).

What is an example of non response bias?

Nonresponse bias can occur for several reasons: The survey is poorly designed and leads to nonresponses. For example, excessively long surveys without incentives may cause a large percentage of people to not complete the survey. Certain people are more likely to respond to a particular survey.

What does overmatching mean in research?

Definition: Overmatching. Overmatching refers to the unnecessary or inappropriate use of matching in a cohort or case control study. To control for potential confounders or to enhance stratified analysis in observational studies, researchers may choose to match cases and controls or exposed and unexposed subjects on characteristics of interest.

How many types of overmatching are there?

From Modern Epidemiology 3rd Edition by Rothman, Greenland and Lash: There are at least three forms of overmatching. The first refers to matching that harms statistical efficiency, such as case-control matching on a variable associated with exposure but not disease.

What is matching that harms statistical efficiency and validity?

The first refers to matching that harms statistical efficiency, such as case-control matching on a variable associated with exposure but not disease. The second refers to matching that harms validity, such as matching on an intermediate between exposure and disease. The third refers to matching that harms cost-efficiency.

What is matching in research?

As I understand it, matching is one way to identify causality in observational studies. By matching observations that are “similar” and comparing ones that did or did not receive treatment, you can consider this as a quasi-experiment of sorts. What is overmatching? What kind of bias does it introduce?