# Research Glossary

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.

Accuracy
In survey research, accuracy refers to the match between a sample and the target population. It also indicates how close a value obtained from a survey instrument or assessment is to the actual (true) value.
Action Research
Action research conducted to solve problems, inform policy, or improve the way that issues are addressed and problems solved. There are two broad types of action research: participatory action research and practical action research.
A measure of how well the independent, or predictor, variables predict the dependent, or outcome, variable. A higher adjusted R-square indicates a better model. Adjusted R-square is calculated based on the R-square, which denotes the percentage of variation in the dependent variable that can be explained by the independent variables. The adjusted R-squared adjusts the R-square for the sample size and the number of variables in the regression model. Therefore, the adjusted R-square is a better comparison between models with different numbers of variables and different sample sizes.
Administrative data are used in support of the operations and service delivery of government departments and other organizations. Examples are information about individual children, families, and/or providers of early care and education and other family benefits and services. The data are collected and maintained primarily for administrative (not research) purposes.
Alpha Level
The probability that a statistical test will find significant differences between groups (or find significant predictors of the dependent variable), when in fact there are none. This is also referred to as the probability of making a Type I error or as the significance level of a statistical test. A lower alpha level is better than a higher alpha level, with all else equal.
Alternative Hypothesis
The experimental hypothesis stating that there is some real difference between two or more groups. It is the alternative to the null hypothesis, which states that there is no difference between groups.
Analysis of Covariance (ANCOVA)
Is an advanced form of ANOVA (analysis of variance). While ANOVA is used to test for differences in the means of two or more groups, ANCOVA removes the effect(s) of one or more continuous variable(s) before testing for the group differences. For example, in an analysis that examines differences in child outcomes by type of child care, the analyst may want to remove the effects of parental education.
Analysis of Variance (ANOVA)
A statistical test that determines whether the means of two or more groups are significantly different.
Anonymity
An ethical safeguard against invasion of privacy whereby the researcher is unable to identify the respondents by their responses.
Association
The relationship between objects or variables. Two variables are positively associated when the values of one increase as the values of the other increases. They are negatively associated when the values of one decrease as the values of the other increase. Income and education are usually positively associated and student absentism is generally negatively associated with student achievement.
Release: 'v1.24.0' | Built: 2023-01-23 14:56:35 EST