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.
Constant
A value that stays the same for all the units of an analysis. For instance, in a research study that explores fathers' involvement in their children's lives, gender would be constant, as all subjects (units of analysis) are male.
Construct
A construct or a concept is a theoretical creation that cannot be directly observed, but can be measured using one or more indicators or tests. Examples of constructs in early care and education research include classroom quality, professional development, reading and math achievement, and socioemotional development.
Construct Validity
The degree to which a variable, test, questionnaire or instrument measures the theoretical concept that the researcher hopes to measure. For example, if a researcher is interested in the theoretical concept of "marital satisfaction," and the researcher uses a questionnaire to measure marital satisfaction, if the questionnaire has construct validity it is considered to be a good measure of marital satisfaction.
Contamination
In an experimental study, contamination occurs when individuals or groups of individuals receive certain features of an intervention intended for a different experimental group. For example, students in an elementary school assigned at random to receive one of three accelerated math curricula, may receive parts of a curriculum that are different from the one to which they were assigned. Or, students who are randomly assigned to a control group in an experimental study of the effects of a new approach to teaching math (treatment) may be exposed to some of the features of the treatment. In educational research, random assignment is often done at the classroom or school level to avoid such contamination.
Content Analysis
A procedure for organizing narrative, qualitative data into themes and concepts. It is used to describe and draw meaning from different forms of written (e.g., books, magazines, newspapers) and oral (e.g., audiotapes, television and videos) communications. Content analysis is used in both quantitative and qualitative research.
Content Validity
Content validity, like face validity, refers to whether a given test or other measurement tool (e.g., classroom observation protocol) actually measures the construct that it claims to measure. Content validity requires the use of recognized experts to evaluate whether test items or items in an observation protocol actually assess the defined content.
Context Conditionality
Context conditionality refers to those situations where the effect(s) of some independent variable(s) on some dependent variable(s) depend upon or are moderated by a third (set of) independent variable(s). One way that researchers address this is by including interaction terms for the independent variables in their models.
Context Effects
The change in the dependent variable which is resulted from the influence of the research environment. This influence is external to the experiment itself.
Continuous Variable
A variable that, in theory, can take on any value within a range. The opposite of continuous is discrete or categorical, which can have only a particular set of values. For example, a person's height could be 5 feet 1 inch, 5 feet 1.1 inches, 5 feet 1.11 inches, and so one, and thus it is continuous. The type of child care setting where a child spends the greatest number of hours each week (e.g., center-based care, relative and nonrelative care) is a discrete or categorical variable.
Control
The processes of making research conditions uniform or constant, so as to isolate the effect of the experimental condition. When it is not possible to control research conditions, statistical controls often will be implemented in the analysis.