Term
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Definition
| -observed effects of the independent variable are real and not caused by extraneous factors. |
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Term
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Definition
| -the ability to generalize study results to settings outside of the current experiment. |
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Term
| Threats to Internal Validity |
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Definition
| -extraneous factors that allow for alternative reasons to effect the dependent variable |
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Term
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Definition
-when events occur between the pretest and posttest of a study that could affect participants and impact the dependent variable
-A control group, not receiving treatment, could be used to compare results with the experimental group who did receive treatment. |
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Term
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Definition
| -A group of participants with the same characteristics of the treatment group that do not receive the treatment. |
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Term
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Definition
| -The group receiving the treatment |
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Term
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Definition
-changes seen in subjects that are a result of the time that has elapsed since the study began and which may not be the result of any program effects
-A control group who does not receive treatment could be used and compared to the experimental group. Differences between the two groups would most likely be the result of the treatment |
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Term
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Definition
| -A measurement taken to obtain the status or level of a variable before initiating a study |
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Term
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Definition
| -participants are able to score higher as a result of being tested multiple times |
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Term
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Definition
-any difference that may be seen from baseline to posttest that is not caused by the independent variable
-A control group that does not receive pretesting will reduce the testing effect |
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Term
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Definition
-individuals are selected in a nonrandom manner will reduce internal validity
-The researcher can reduce this bias by randomly selecting participants from the volunteering population. Matching participants on specific criteria and randomly assigning them to groups can also help. |
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Term
| Selection Maturation Effect |
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Definition
-occurs with the use of intact groups that vary in their maturation levels
-In order to control this, researchers can pretest groups based on maturity levels. |
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Term
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Definition
| -A random sample of participants that may be generalized to some degree |
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Term
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Definition
| -general persons who had a chance to be randomly chosen as a study participant |
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Term
| Setting Treatment Interaction |
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Definition
-A threat to external validity. The extent to which the environmental conditions under which an experimental study was conducted can be duplicated in other settings
-i.e. two schools receiving the same treatment but differing in socioeconomic status, career aspirations, family support, etc. The students who are more "well-off" will be more susceptible to the treatment. |
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Term
| History Treatment Interactions |
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Definition
-A threat to external validity when the researcher tries to generalize findings to past and future situations.
-i.e. Differences of results from a smoking cessation program in January (after New Years Resolutions) compared to June. |
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Term
| Analysis of Covariation (ANCOVA) |
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Definition
| -A fairly powerful statistical procedure that can be used to equalize many initial differences that may exist between groups |
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Term
| Selection Treatment Interaction |
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Definition
-A threat to external validity that concerns the ability of a researcher to generalize the results of a study beyond the groups involved in the study (overgeneralizing)
-"Is the experimental group representative of the general population?" Did all persons have an equal chance of being chosen for the study population? |
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Term
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Definition
-Occurs when participants are selected because of their extremely high or low scores from one test, and separated into groups accordingly.
-A random sample of participants representing the full range of scores should be selected and observed. |
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Term
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Definition
-The loss of subjects between pretesting and posttesting due to death, drop outs, expired contact information, etc.
-Hard to counteract, creates bias, causes problems in terms of comparisons and generalizing. |
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Term
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Definition
-Participants attitudes and behaviors are affected by being in a study
-To counteract this effect, researchers can expose the control group to another form of treatment that is comparable to the experimental group, but will not effect the dependent variable. Any differences found will likely be from the treatment and not the attention given. |
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Term
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Definition
-results caused by participants' expectations rather than the provided treatment
-To control this, the control group receives a placebo that they believe to be real treatment. |
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Term
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Definition
| -An inactive substance that looks like the real drug |
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Term
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Definition
| -Participants involved in a study do not know whether they are receiving the real drug or the placebo |
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Term
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Definition
| -the researcher as well as the participants are unaware of who is receiving the real drug versus the placebo |
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Term
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Definition
-When the treatment of one group contaminates another group (experimental group exposes treatment to the control group)
-To control this, clarify the confidentiality of treatment procedures OR find a control group in a separate environment that has the same characteristics as the experimental group. |
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Term
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Definition
-Occurs when there are differences in the locations where interventions take place (i.e. the setup and environment of the room)
-Researchers should test participants in the same place if possible OR minimize environmental differences between locations as much as possible. |
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Term
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Definition
-Occurs when the individuals responsible for implementing the experiment inadvertently introduce bias into the study. (i.e. Multiple treatment providers may have differences in their knowledge of the procedure, personality, presentation skills, etc.)
-Researchers can make sure all persons are equally trained and follow a standardized protocol for implementation. |
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