Experimental design principles and methods

Experimental Design

Background of the Experiment

The subject matter of this experiment is the effect of direct and indirect intervention in connection with the expressed attitudes of adolescents about responsible and irresponsible alcohol consumption. To test the effect of direct intervention, teenagers will be exposed to explicit conversational messages from parents about the dangers of irresponsible drinking and about strategies for drinking alcohol responsibly. To test the effect of indirect intervention, teenagers will be exposed to implicit messages in the form of modeled behaviors without explicit verbal messages. In the pretest/post-test version of the experiment, responses will be compared before and after the exposure to the intervention. In the post-test, responses of the test group following exposure to the intervention will be compared to those of a control group not exposed to the intervention.

Experimental Framework

Pre-test/Post-test Control Group

Twenty adolescents will be engaged in a written "Attitudes and Beliefs" pretest consisting of multiple choice questions designed to identify the strengths of various beliefs about the relative importance of responsible alcohol consumption among adults. To reduce the potential influence of the pretest on outcome, the five questions pertaining to the test subject will be embedded within three sets of five questions on other topics, such as parenting, academic honesty, and the importance of obeying laws. Following the intervention exposures, the test subjects will be given similar post-tests featuring the identical breakdown and order of questions by subject matter except that all of the questions were different forms of the pretest questions. The relative strength of responses to sets of similar questions in the two tests will be compared.

Post-test Control Group

Following the intervention exposures, twenty adolescent test subjects will be engaged in the written "Attitudes and Beliefs" prost-test used in the pretest/post-test used in the first experimental design. The test will consist of multiple choice questions designed to identify the strengths of various beliefs about the relative importance of responsible alcohol consumption among adults. To reduce the potential influence of the pretest on outcome, the five questions pertaining to the test subject were embedded within three sets of five questions on other topics, such as parenting, academic honesty, and the importance of obeying laws. The relative strength of responses of the test group will be compared to the answers furnished by a control group that was tested without any prior exposure to the intervention.

Hypotheses

Hypothesis # 1- Exposure to interventions will increase the strength of beliefs indicating disapproval of irresponsible drinking and indicating appreciation of the importance of responsible drinking.

Independent Variable 1: Exposure to Direct Intervention. Dependent Variable 1:

Strength of Expressed Opinions on Questionnaire.

Independent Variable 2: Exposure to Indirect Intervention. Dependent Variable 2:

Strength of Expressed Opinions on Questionnaire.

Hypothesis # 2- Exposure to the indirect intervention will increase the strength of beliefs indicating disapproval of irresponsible drinking and indicating appreciation of the importance of responsible drinking more than exposure to direct intervention.

Independent Variable 1: Exposure to Direct Intervention. Dependent Variable 1:

Strength of Expressed Opinions on Questionnaire.

Independent Variable 2: Exposure to Indirect Intervention. Dependent Variable 2:

Strength of Expressed Opinions on Questionnaire.

Variables

Direct Intervention -- Test subjects will be exposed to conversation at the dinner table directed to them and including them on three separate occasions one week apart about the importance of consuming alcohol responsibly and about the dangerous consequences of drinking irresponsibly.

Indirect Intervention -- Test subjects will be exposed to modeled behavior of adults expressing concern over matters such as designating a non-drinking driver and avoiding excessive intoxication without any conversation about them or directed to them three separate occasions one week apart.

Controls

There will be a control condition in the post-test version of the experimental design. Specifically, the responses of test subjects will be compared to a comparable control group that is not exposed to the specified intervention.

Manipulation Check

The parents will be instructed to either engage in verbal conversation directly with the test subjects or to refrain from any involvement with the test subjects while engaging in conversation with another adult about adults in their presence. The parents will be asked to confirm their adherence to this protocol after the fact. To ensure that the test subjects heard the conversation directed at them, they will be asked a direct question. To confirm that the subjects heard the conversations not directed at them, they will be engaged in a casual comment and glance in which the parent will say something along the lines of "Your mother and I feel that you are too old to be told to leave the room when we discuss these kinds of things but we expect you never to repeat anything you happen to overhear when we discuss other adults."

Sampling and Ethical Considerations