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Definition
Occurs when an event occurs between the pre- and posttest that could affect participants in a way that would impact the DV.
A researcher can address this concern by using a control group and an experimental group. |
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Definition
Occurs when changes are seen in subjects because of the time that has elapsed since the study began.
A researcher can address this concern by using a control group and an experimental group. |
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Term
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Definition
| A measurement taken to obtain the status of level of a variable prior to initiating a study. NOT A THREAT. |
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Definition
Occurs when there are any differences that are seen from baseline to posttest that are not as a result of the independent variable.
A researcher may address this concern by using a control group and an experimental group. |
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Definition
Occurs when the instrumentation used to collect data during a study affects the study due to inaccuracy or not being standardized.
A researcher can address this concern by using well-designed instruments. |
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Definition
Occurs when individuals are not randomly assigned or selected.
Researchers can address this concern by using pretests to minimize or eliminate pretreatment differences between groups. |
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Term
| Selection Maturation Effect |
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Definition
Occurs when the combination of selection bias and maturation threat threatens internal validity.
A researcher can address this concern by pretesting or prescreening groups on maturity levels. |
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Definition
Occurs when participants are selected because they had very low or very high scores on an instrument.
A researcher can address this concern by selecting participants from the full range of scores. |
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Term
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Definition
Occurs when a study some of the original participants.
Researchers can address this concern by using large groups, using incentives to encourage participants to remain in the study, and by documenting and analyzing the loss. |
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Term
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Definition
Occurs when participant' attitudes towards being in a study influences how they behave in the study.
Researchers can address this concern by not letting participants know that they are in the study, or by treating the control and experimental group the same so that some level behavior change is controlled for. |
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Term
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Definition
Occurs when participants behave differently because of expectations they hold about what should or should not occur.
The researcher can address this concern by providing little information about possible effects and by giving the control and experimental groups the same information. |
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Term
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Definition
| A study where participants do not know if they are in the control or experimental group, but the researcher does. NOT A THREAT. |
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Term
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Definition
| A study where neither researchers nor participants know which participants are in the control and experimental groups. NOT A THREAT. |
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Term
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Definition
Occurs when the treatment being applied to the experimental group spills over or contaminates the control group.
Researchers can address this concern by emphasizing confidentiality about the study to the treatment group. |
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Term
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Definition
Occurs when there are differences in the locations where the interventions take place.
Researchers can address this concern by using the same location for all participants, or by minimizing location differences if this is not possible. |
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Term
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Definition
Occurs when the individuals who are implementing the treatment introduce any bias into the study.
Researchers can address this by making sure that the individuals implementing the treatment are trained, competent, and neutral about the results and participants of the study. |
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Term
| Selection Treatment Interaction |
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Definition
Occurs when a researcher generalizes the results of the study beyond the groups involved in the study.
Researchers can address this concern by being careful to only generalize the results to individuals who could have been randomly selected from the study population. |
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Term
| Setting Treatment Interaction |
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Definition
Concerns whether environmental conditions or settings of the study can be duplicated in other settings.
The researcher must be aware of differences between the experimental study settings and setting beyond the study. |
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Term
| History Treatment Interaction |
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Definition
Occurs when the researcher attempts to generalize findings to past and future situations.
Researchers must be cognizant that the time period that the study is conducted in is crucial to the results of the study. |
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