The research glossary defines terms used in conducting social science and policy research, for example those describing methods, measurements, statistical procedures, and other aspects of research; the child care glossary defines terms used to describe aspects of child care and early education practice and policy.
The actual unit observed during a study in order to measure something about it. In child care and early education research typical observation units include programs and schools, classrooms and teachers, children and their parents.
A way to express a probability; the ratio of the odds of having a response or experience to the odds of not having it.
Omitted Variable Bias
A form of bias in research resulting from the absence of key variables into the research design that would influence the results. When there is omitted variable bias, the results of the study could be due to alternative explanations that are not addressed in the study.
Omitted Variable Sensitivity Analysis
Omitted variable sensitivity analysis is used to assess the influence of not including one or more variables on the relationship between an independent variable X and a dependent or outcome variable Y. It quantifies how large the effect of the omitted variable or variables would have to be in order to invalidate or explain away the association between X and Y. For example, the correlations between the omitted variable and the independent and dependent variables would have to be of a specified value in order to invalidate the finding that X and Y are significantly associated.
A test of whether the mean for more than two groups are different. For example, to test whether the mean income is different for individuals who live in France, England, or Sweden, one would use a one-way ANOVA.
Data derived from open-ended inquiries, such as interview questions, to which responses are not predetermined, such as would be the case with multiple choice or true/false questions.
Matching is a technique that is used to evaluate the effect of a treatment (intervention) when those who receive the treatment and those who do not have not been randomly assigned. The goal of matching is, for every treated subject (participant), to find one (or more) subjects who have not received the treatment but who have similar characteristics (e.g., age, gender, achievement test scores) to those who have. Matching enables a comparison of outcomes among those treated and those not treated in order to estimate the effect of the treatment. Optimal matching is a global matching approach that looks to minimize the distance (differences) between matched subjects.
Data that are categorical, but that can also be ranked (ordered). However, the distance between the categories is not known and may not be equal. For example, parents might rate their satisfaction with their child's child care provider as "very dissatisfied," "dissatisfied," "satisfied," and "very satisfied." using numerical values of 1, 2, 3 and 4, respectively. A parent with a satisfaction score of 1 is more dissatisfied than a parent with a score of 2, but not necessarily twice as dissatisfied. And the difference between scores of 1 and 2 and scores of 3 and 4 are not necessary the same.
A scale that allows for classification and labeling into mutually exclusive categories based on features that are ranked or ordered with respect to one another, although equal differences between numbers do not reflect an equal magnitude of difference.
Ordinary Least Squares Estimation
A commonly used method for calculating a regression equation. This method minimizes the difference between the observed data points and the data points that are estimated by the regression equation.