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Resolving Internal Validity Threats in an Experiment Design

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Consider the following scenario:

60 children, ages 3-5, are selected to participate in a program for developing non-verbal communication skills. The children were selected on the basis of extremely low scores on a test of non-verbal communication. After participating in the program, the children are re-tested. An average improvement of 59% is observed in the quality of non-verbal communications.

What threat to internal validity is present in this situation? How can this confound be eliminated?

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https://brainmass.com/sociology/research-methods/resolving-internal-validity-threats-in-an-experiment-design-577878

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In my opinion the biggest threat to internal validity is the huge age range for the participants. Depending on how the program is designed and implemented, a certain age may benefit more from the program. However, the age range is a concern too due to the different rates of maturation of the participants. The different ages will be maturing differently and acquiring slightly different skills due simply to their age. Yet maturation in general is an internal ...

Solution Summary

The solution picks out and explains a threat to the validity of the given non-verbal communication skills study, as well as giving suggestions on how to remove it. 280 words with 3 reference links.

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See Also This Related BrainMass Solution

Statistics Questions - quasi-experiments

A. Complete Jackson Even-numbered chapter exercises, p, 360

1Describe the advantages and disadvantages of quasi-experiments? What is the fundamental weakness of a quasi-experimental design? Why is it a weakness? Does its weakness always matter?
2If you randomly assign participants to groups, can you assume the groups are equivalent at the beginning of the study? At the end? Why or why not? If you cannot assume equivalence at either end, what can you do? Please explain.
3Explain and give examples of how the particular outcomes of a study can suggest if a particular threat is likely to have been present.
4Describe each of the following types of designs, explain its logic, and why the design does or does not address the selection threats discussed in Chapter 7 of Trochim and Donnelly (2006):
Non-equivalent control group pretest only
Non-equivalent control group pretest/posttest
Cross-sectional
Regression-Discontinuity
5Why are quasi-experimental designs used more often than experimental designs?
6One conclusion you might reach (hint) after completing the readings for this assignment is that there are no bad designs, only bad design choices (and implementations). State a research question for which a single-group post-test only design can yield relatively unambiguous findings.

Part II - Answer the following questions:
1What research question(s) does the study address?
2What is Goldberg's rationale for the study? Was the study designed to contribute to theory? Do the results of the study contribute to theory? For both questions: If so, how? If not, why not?
3What constructs does the study address? How are they operationalized?
4What are the independent and dependent variables in the study?
5Name the type of design the researchers used.
6What internal and external validity threats did the researchers address in their design? How did they address them? Are there threats they did not address? If so how does the failure to address the threats affect the researchers' interpretations of their findings? Are Goldberg's conclusions convincing? Why or why not?
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