Some city health officials did not want to place food trucks at the Alcan City Fair. They felt that it did not add value to the fair and that it promoted unhealthy nutritional choices for the fair attendees. Could these opinions create bias in the studies that the city health officials conducted? Did the personal views of the Alcan City health officials influence the outcomes of their study and the interpretation of the data gathered?
Bias refers to deviations of results, or inferences, from the truth (Friis & Sellers, 2021). There are two overarching types of bias: information bias and selection bias. Both types can be detrimental to the validity and reliability of results. Several strategies exist to help prevent bias, but it is virtually impossible to eliminate bias altogether. In addition to bias, confounding variables can pose challenges for epidemiologists. Confounding is the masking of an association between an exposure and an outcome because of the influence of a third variable that was not considered in the study design or analysis. For example, if weight loss is the topic of study and exercise is the only variable considered, diet could mask the results of the study.
In this Discussion, you will review different types of bias, present an example of a study, and discuss whether bias was a factor in the study outcome. You will also discuss how the study design could have been altered to minimize or eliminate the risk of invalidating the results.
Friis, R.H., & Sellers, T.A. (2021). Epidemiology for public health practice (6th ed). Jones & Bartlett Learning.
To prepare for this Discussion:
Review the types of bias discussed in your textbook and listed below:
- Non-differential recall bias
- Differential recall bias
- Publication bias
- Loss to follow-up
- Refusal to participate
- Interviewer bias
Select two types of bias from the list above, or from those discussed in Chapter 10 of the Friis and Sellers (2021) text, and consider the ways that bias could impact a study.
By Day 4
Post a summary of a real or hypothetical study. You can use one of the studies you designed during Weeks 3 or 4, or search for a different study.
- Identify at least two ways that bias may be introduced in the study, and indicate which type of bias each one is—selection bias or information bias. Explain your answer.
- Identify any evidence of causal relationships in the study you have selected. Explain your answer.
- Describe measures of statistical and clinical significance that the study may have.
- Identify two confounding variables that might influence your study, and explain how they could affect the results.
- Describe at least one method of controlling the confounding variables you identified.
Use complete sentences in writing your Discussion post, cite your sources, and include references in APA format. Ensure that your in-text citations and reference list are in APA format. For more information on APA style, use the following Walden University resource:
- Walden University Writing Center. (2019). APA style: Overview. Retrieved from https://academicguides.waldenu.edu/writingcenter/apa
Read a selection of your colleagues’ postings.
By Day 6
Respond to at least two of your colleagues’ postings in one or more of the following ways:
- Identify a different type of bias might be introduced in your colleague’s study and determine whether it is selection or information bias.
- Identify an additional confounding variable in your colleague’s study and explain at least one method of controlling the confounding variable you identified.