Assent
Agreement to participate in a study, sought from minors.

Bias
Any influence that produces a distortion in the results of a study.

Confounding variables
Variables that are not controlled in a study which may influence the outcomes.

Consent
Agreement by a person of legal adult status to participate in a study, usually in the form of a written document outlining the terms and conditions of a subject's voluntary participation.

Control group
Subjects in an experiment who do not receive the experimental treatment and whose performance provides a baseline against which the effects of the treatment may be measured.

Differential attrition
The unequal loss of subjects from one or more study groups, which may introduce bias by changing the composition of the sample initially selected.

Double-blind
A condition in which neither the subject nor the researcher administering the treatment know who is in the experimental or control group.

Exclusion criteria
Criteria thought to be potential confounding variables excluding people from participating in a study.

True experimental design
A study design incorporating three essential criteria: (a) an intervention; (b) presence of a control group; and (c) random assignment to intervention or control group.

Inclusion criteria
Criteria used to include people with similar characteristics in a study.

Independent variables
Variables thought to have an effect on, or influence the dependent variable. In experimental research, this is the variable that is manipulated.

Interaction effect
When two or more independent variables interact with each other to effect the dependant variable.

Outcome variable
Also known as the dependant variable, is the measure that captures the outcome of the intervention.

p value
In statistical testing, the probability that the results obtained occurred due to chance alone. If one sets the p value at traditional 0.05 significance level, one is willing to accept the 1:20 or 5% probability that the obtained results occurred by chance alone.

Placebo-controlled

advertisement

Subjects in the control group get a similar intervention, but one that does not contain the active ingredient. Subjects who receive a placebo provide a performance baseline against which the effects of the active treatment may be measured.

Placebo effect
A condition in which subject knowledge of being included in a study is sufficient to change the participant's behavior or perceptions, regardless of the intervention.

Placebo run-in
A time period during which both the experimental and placebo groups receive placebo conditions, to evaluate for changes simply by administering "something." Subjects who respond to this placebo trial are often not included in the main trial.

Power
The ability of a study to detect existing significant differences or relationships among variables.

Random assignment or randomization
The researcher assigns subjects to a control or intervention group on a random basis, thus reducing systematic bias in the groups with respect to characteristics that may affect the dependent variable.

Single-blind
A condition in which the subject does not know whether they are receiving the active or placebo intervention, however, the researcher administering the intervention does know the status of the subject.

Standardized instruments
Questionnaires, interviews, and/or other measuring devices that have been tested, normed to a population, and are considered valid and reliable.

Validity
The accuracy or degree to which an instrument measures the variable it is intended to measure.

Abramowicz, M. (1990). Sudden death in children treated with a tricylic antidepressant. The Medical Letter on Drugs and Therapeutics, 32, 53.

Beck, A.T. (1996). Beck Depression Inventory-IL San Antonio, TX: The Psychological Corporation.

Birmaher, B., Ryan, N.D., Williamson, D.E., Brent, D.A., Kaufman, J., Dahl, R.E., Perel, J., & Nelson, B. (1996). Childhood and adolescent depression: A review of the past 10 years. Part I. Journal of the American Academy of Child and Adolescent Psychiatry, 35, 1427-1439.

Emslie, G.J., Rush, A.J., Weinberg, W.A., Kowatch, R.A., Hughes, C.W., Carmody, T., & Rintelman, J. (1997). A double-blind, randomized, placebo-controlled trial of Fluoxetine in children and adolescents with depression. Archives of General Psychiatry, 54, 1031-1037.

Hodgeman, C., Kaplan, S., Kazdin, A., & van Dalen, A. (1993, May 30). Managing depression in children. Patient Care, 51-60.

Kaslow, N.J. & Thompson, M.P. (1998). Applying the criteria for empirically supported treatments to studies of psychosocial interventions for child and adolescent depression. Journal of Clinical Child Psychology, 27, 146-155.

Kovacs, M. (1992). Children's Depression Inventory. North Towanda, NY: Multi-Health Systems.

Kutcher, S. (1997). Practitioner review: The pharmacology of adolescent depression. Journal of Child Psychology and Psychiatry, 38, 755-767.

Kye, C.H., Waterman, G.S., Ryan, N.D., Birmaher, B., Williamson, D.E., Iyengar, S., & Dachille, S. (1996). A randomized, controlled trial of Amitriptyline in the acute treatment of adolescent major depression. Journal of the American Academy of Child and Adolescent Psychiatry, 35, 1139-1144.

Melnyk, B.M., & Moldenhauer, Z. (1999). Current approaches to depression in children and adolescents. Advance for Nurse Practitioners, 7(2), 24-29, 97.

Rao, U., Ryan, N.D., Birmaher, B., Dahl, R.E., Williamson, D.E., Kaufman, J., Rao, R., & Nelson, B. (1995). Unipolar depression in adolescents: Clinical outcome in adulthood. Journal of the American Academy of Child Psychiatry, 34, 566-578.

Reynolds, W.M. (1989). Reynolds Child Depression Scale. Lutz, FL: Psychological Assessment Resources.

Reynolds, W.M., & Johnston, H.F. (1994). Handbook of depression in children and adolescents. New York: Plenum Press.

Richardson, L.A., Keller, A.M., Selby-Harrington, M.L., & Parrish, B. (1996). Identification and treatment of children's mental health problems by primary care providers: A critical review of research. Archives of Psychiatric Nursing, 10(5), 293-303.

Riddle, M.A., Geller, B., & Ryan, N. (1993). Another sudden death in a child treated with Desipramine. Journal of the American Academy of Child and Adolescent Psychiatry, 32, 792-797.