CONTROL GROUP: A group of SUBJECTS who receive no TREATMENT. The control group provides the researcher with a means of evaluating the effects of the treatment by comparing the TREATMENT GROUP and the control group after the treatment has been received.

CASE STUDY: an in-depth study of one individual or situation. The data in such a study may be recorded in field notes, typically a chronological account of both formal and informal observations. These notes are summarized and usually analyzed using some form of coding that identifies important trends and relationships in the data.

DESCRIPTIVE STUDY: a study that focuses on a particular situation or set of situations, reports on important aspects observed, and attempts to determine the interrelationships among them.

LONGITUDINAL STUDY: A study that evaluates changes in SUBJECTS over time.

N: The number of SUBJECTS who participate in a study.

POST-TEST: A test given to the SUBJECTS of a research study after the study has been completed. The post-test allows the researcher to evaluate the effects of the TREATMENT.

PRE-TEST: A test given to the SUBJECTS of a research study before the study begins. The pre-test provides data from which the effects of the TREATMENT may be measured.

SUBJECT: a person participating in a research study.

TREATMENT: a situation controlled by the researcher that exposes the SUBJECTS to the variable being studied; e.g., "pitch pattern instruction" or "piano accompaniment."

TREATMENT GROUP: a group of SUBJECTS that experiences a treatment containing the variable being studied; e.g., the children who are in the group that experiences "pitch pattern instruction."