6301 wk 7 discussion
2
RESPONSE 1
Collapse Subdiscussion Andrea Marie Arra Davison
Andrea Marie Arra Davison ( She/Her)
12:56pmApr 11 at 12:56pm
What is the difference between internal and external validity?
Internal validity is a question of whether or not the research measures what it is supposed to measure (Yegidis et al., 2018, p. 119). For example, is the independent variable causing changes in the dependent variable? Or is equine-assisted therapy improving social functioning in children with autism?
External validity, conversely, is whether or not the research applies to the population of interest (Yegidis et al., 2018, p. 122). Are the findings generalizable? For example, do the conclusions that equine-assisted therapy improves social functioning in children with autism apply to all children with autism? How well do we know our findings are true for other children with autism?
Select two internal validity threats and describe each.
Two threats to internal validity are regression to the mean and lack of sample comparability.
Regression to the mean refers to the tendency of individuals, on repeated measures, to move toward the mean or average scores for a given measure (American Psychological Association [APA], n.d.; Yegidis et al., 2018). For example, someone with a very high or a very low score on a test will tend, statistically speaking, to fall closer to the mean or average in subsequent testing. This tendency to regress to the average will mean that extreme scores will not necessarily be representative of a population and may threaten internal validity. Yegidis et al. (2018) describe a situation where intentionally choosing individuals from a population with extreme scores will impact internal validity. When the researchers look at or investigate extreme cases or individuals with extreme scores, the tendency to regress toward the mean will be more likely (p. 120). In other words, the chance that the resulting follow-up scores will be more representative of this statistical regression effect versus an intervention effect will be more likely.
Lack of sample comparability or variation between samples threatens internal validity. The samples used in the control groups and treatment/intervention groups in an experimental design should ideally be as similar as possible to reduce the likelihood that the effects of the intervention are due to some other factor in the sample (an extraneous variable). For example, let us say I had two groups in my research regarding the effects of equine-assisted therapy (the intervention group and the control group). Let us say that one of the groups had individuals with more severe autism, was predominantly female or had highly educated parents. How could I be sure that the intervention caused the improvements in social functioning and not one of the other factors?
After examining each category and list of designs, determine which design controls for all threats to internal validity. Explain how this design controls for all threats.
The best design to aid in controlling for all threats to internal validity is the experimental design and, even more specifically, randomized controlled designs (Akobeng, 2005; Yegidis et al., 2018, p. 122). This design controls for all threats by randomization of participants into control groups. Randomization ensures that all participants are equally likely to be in either the control or the intervention group. This randomized assignment to groups makes it more likely that the samples will have a similar variation of characteristics that could influence the results. Attributes like having extremely high scores, being all female, or from affluent parents, etc., would have more of a likelihood of being balanced between groups.
References
Akobeng, A. K. (2005). Understanding randomized controlled trials. Archives of Disease in Childhood, 90, 840-844. https://doi.org/10.1136/adc.2004.058222Links to an external site.
American Psychological Association. (n.d.). APA dictionary of psychology: Regression toward the mean. https://dictionary.apa.org/regression-toward-the-meanLinks to an external site.
Yegidis, B. L., Weinbach, R. W., & Myers, L. L. (2018). Research methods for social workers (8th ed.). Pearson
References
English, D., Lambert, S. F., Tynes, B. M., Bowleg, L., Zea, M. C., & Howard, L. C. (2020). Daily Multidimensional racial discrimination among Black U.S. American adolescentsLinks to an external site. Journal of Applied Developmental Psychology, 66. https://doi.org/10.1016/j.appdev.2019.101068
Zastrow, C. H., Kirst-Ashman, K. K., & Hessenauer, S. L. (2019). Understanding human behavior and the social environment (11th ed.). Cengage Learning. Chapter 5, “Ethnocentrism and Racism” (pp. 233–281)
RESPONSE 2
Collapse Subdiscussion Kevin Menard
YesterdayApr 10 at 2:28pm
What is the difference between internal and external validity?
Internal and external validity assess whether or not the findings of a study are trustworthy, dependable, and relevant. Internal validity investigates a dependable cause and effect outcome between the therapy and the study's outcome. Internal validity is when you can be confident that a cause-and-effect relationship identified in a study cannot be clarified by other factors (Yegidis et al., 2018). Internal validity is based on the belief that what is being tested will not be influenced by external variables. Diffusion, historical events, and testing are examples of factors that can improve a study's internal validity (Cuncic, 2022).
External validity refers to how the results of a study can be extended to different settings, such as persons, situations, and time periods. External validity can be improved by applying inclusion and exclusion criteria and conducting field experiments, among other things (Cuncic, 2022). The amount to which the findings of a study may be generalized to other situations, persons, places, and measures is referred to as external validity (Yegidis et al., 2018).
Select two internal validity threats and describe each.
History is an example of an internal validity threat. This occurs when an event occurs during the research that has an effect on the dependent variable (Yegidis et al., 2018). It could also be a true historical occurrence, such as a natural disaster. The term "history" refers to the occurrences that can occur between one's first and second measurements. Any modifications in instruments or observers that potentially affect the outcomes of a study are referred to as instrumentation. The traditional controlled experimental design employs random assignment, an experimental and control group, as well as pre-testing and post-testing. The benefit of this type of testing is that it is random, thus any differences that occur in the post-test should be due to the experimental variable rather than a possible difference between the two groups that it started with. A lack of sample comparability is another example of a threat. This suggests that the study's groups were not comparable to begin with (Yegidis et al., 2018).
After examining each category and list of designs, determine which design controls for all threats to internal validity. Explain how this design controls for all threats.
True experiment designs allow us to rule out the possibility of any other factors (apart from the independent variable) influencing the dependent variable (Yegidis et al., 2018). According to our text, the Solomon four-group design meets this condition. It employs a pre-test and a post-test, allowing the researcher complete control over the variables and ensuring that the pre-test had no effect on the outcomes (Yegidis et al., 2018).
References
Cuncic, A. (2022, October 17). Internal Validity vs. External Validity in Research Both help determine how meaningful the results of the study are. Verywellmind.com. Retrieved April 10, 2023, from https://www.verywellmind.com/internal-and-external-validity-4584479Links to an external site.
Yegidis, B. L., Weinbach, R. W., & Myers, L. L. (2018). Research methods for social workers (8th ed.). Pearson.