Step 1 Read the article in Appendix D “Example of a Correlational Study” (Turner et al., 2016).
Step 2 Discuss the following questions related to the article found on ~ p. 177 under Critical Appraisal Criteria:
1. What quasi-experimental design is used in the study, and is it appropriate?
2. What does the author say about the limitations of the study?
3. What are the most common threats to internal and external validity?
Step 3 Read and respond to two other students’ posts by Friday 11:59pm MT.
Read other students’ posts and respond to at least two of them. Use your personal experience, if it’s relevant, to support or debate other students’ posts. If differences of opinion occur, debate the issues professionally and provide examples to support your opinions.
Cite any sources in APA format.
See rubric for grading details
Dorothy Said:
Week 5 Discussion: Quasi-experimental Design
What quasi-experimental design is used in the study, and is it appropriate?
The quasi-experimental design in this study is correctional and descriptive. A descriptive quasi-experimental design is used to describe a phenomenon, behavior, or characteristics of a group of individuals or a population. A great example of a descriptive quasi-experimental design is the prevlance of an specific disease. A correctional quasi-experimental design compare two or more variables with the purpose to identify any relationship between the variables. For example, one might use this design to evaluate the relationship between smoking and lung cancer. In both of these types of design the researcher does not have full control over the variables.
What does the author say about the limitations of the study?
The author states that due to the size of the sample the seedy might be compromised and limited. In this study, the sample consisted of primarily European/Canadian middle class subjects impacting the numbers in at the end. Perhaps if the study was elaborated with more variables the results of the design could have been more diverse.
What are the most common threats to internal and external validity?
According to ”Andrade, C. (2018)” Internal validity examines whether the manner in which a study was designed, conducted, and analyzed allows trustworthy answers to the research questions in the study. While, External validity examines whether the findings of a study can be generalized to other contexts. Studies are conducted on samples, and if sampling was random, the sample is representative of the population, and so the results of a study can validly be generalized to the population from which the sample was drawn (paragraph 4 & 5). Some common threats towards Internal validity is attrition bias which can affect the relationship between your variables. Some common threats for external validity are selection bias, history, and situation effect. They can affect your experiment overall causing the alteration between your results.
References
Andrade, C. (2018). Internal, external, and ecological validity in research design, conduct, and evaluation. Indian journal of psychological medicine. Retrieved May 1, 2023, from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6149308/
MASON SAID:
What quasi-experimental design is used in the study, and is it appropriate?
“The quasi-experimental design, just like a true experiment, aims to identify the cause-and-effect relationship between two variables; the independent and dependent variable” (What Is a Quasi-Experimental Design? – Voxco, 2021). This experimental design has advantages and disadvantages. Advantages being that they don’t use artificial laboratory settings. There’s no random study of assignment. Making it also less expensive.
What does the author say about the limitations of the study?
The limitations of the study are also the same as some of the advantages. There is no random study. Randomization is not used, limiting the study’s ability to conclude a causal association between an intervention and an outcome. “Compared to true experiments, quasi-experimental studies have lower internal validity and therefore aren’t as effective in establishing causality” (What Is a Quasi-Experimental Design? – Voxco, 2021).
What are the most common threats to internal and external validity?
“Internal validity refers to the degree of confidence that the causal relationship being tested is trustworthy and not influenced by other factors or variables. External validity refers to the extent to which results from a study can be applied (generalized) to other situations, groups, or events” (Streefkerk, 2019). I think without the randomization, the trust worthiness isn’t there. The people would rather see research that is based on a random pick of people, laboratory testing, and proof of how it works. Having a control group and differences between the ones experimented on is important.
References
What is a Quasi-Experimental Design? – Voxco. (2021, September 29). https://www.voxco.com/blog/what-is-a-quasi-experimental-design/#:~:text=The%20quasi%2Dexperimental%20design%2C%20similar
Streefkerk, R. (2019, May 15). Internal vs. External Validity | Understanding Differences & Threats. Scribbr. https://www.scribbr.com/methodology/internal-vs-external-validity/#:~:text=What%20are%20threats%20to%20external