Epidemiologic Traps Exercise

For each scenario below,

a.Assign the error or bias most fitting (confounding error, ecological fallacy, effect modification error, recall bias, selection bias.

b.Provide a thorough rationale for your assignment.

c.Provide a remedy to avoid the error or bias.

1.A team of visiting polio eradication workers were informed during their orientation session that population-wide studies done in their host country showed that the risk of polio in villages of that country was strongly epidemiologically associated with the village’s economic/human development circumstances, which ranged greatly from village to village.In some villages, residents lived in hand-constructed huts with no running water, no latrines or sewage disposal areas, and no electricity.In other places, residents lived in wooden or adobe homes which, though modest by Western standards, had all of the above services in place and whose street side craft shops and food markets did a brisk business, catering both to locals and visitors.

Knowing this information, the team went into several villages and attempted to assign a “human development rating” to each family.This was based on that family’s income situation, access to running water, access to elementary school for their children, and the condition of the home. To their surprise, they found that families in all the villages had no difference in polio risk based on the family’s human development rating.

	Answer
a.Error:
b.Rationale:
c.Remedy:

2.A group of athletic trainers found that injuries sustained by basketball players wearing white uniforms led to significantly faster recovery times than similar injuries sustained by players wearing uniforms of any other color.It did not make sense in terms of cause and effect, and yet the data were rechecked, found to be correct, and the relationship persisted when analyzed at several Universities over a period of several years.

	Answer
a.Error:
b.Rationale:
c.Remedy:

3.A researcher wanted to know whether people in the U.S. who had had many dental X-rays were better informed about the risks of radiation from those X-rays than people who had had few or none.Ads were placed in community newspapers, on line at information tech websites, and in a selection of dental offices nationwide for volunteers to log in and complete a survey asking those questions. To her surprise, the researcher found that in her sample, there was no association between the number of X-rays a subject had had, and that subject’s knowledge level about radiation exposure.The researcher reviewed her findings with her faculty advisor, who agreed with her that her results were likely to be inaccurate.

	Answer
a.Error:
b.Rationale:
c.Remedy:

4.200 women who were survivors of breast cancer, and 200 women from the community with no history of cancer, matched for age and parity, were surveyed about a variety of prior exposures that could have a relationship to the development of breast cancer.Several items, including family history in third degree relatives, and history of exposure to specific types of pain relievers during the teen years, came up with significant odds ratios by chi-square test. The researchers analyzed the data in several different subgroups, always with the same result.Encouraged by their findings, they submitted their manuscript to a peer-reviewed journal, which promptly rejected it.

	Answer
a.Error:
b.Rationale:
c.Remedy:

5.A new, popular energy drink was tested in a population of college students in the northeastern USA from November through April.The promoters were encouraged because, at least if consumption could be held to reasonable levels and students could be convinced to space out the consumption throughout the week and to stay on a reasonably balanced diet, there seemed to be no harmful side effects from the drink.

Eager to cash in on the benefits, a competing company tested its drink, made from almost exactly the same formula, in college students in the southwestern USA for five months beginning in May. They made sure that the diet and consumption patterns were the same as in the other group.Unexpectedly, they found that a high percentage of this group of students, both young men and young women, developed a blotchy appearance to the skin of their faces and arms after drinking the energy drink, which persisted throughout the day of consumption and into the next.If they stopped drinking the drink, the blotches quickly cleared up.

	Answer	Points
a.Error:
b.Rationale:
c.Remedy:

Resources

Textbook: Katz, D., Elmore, J., Wild, D., Lucan, S. (2013). Jekel's epidemiology, biostatistics, preventive medicine, and public health (4th ed). New York, NY: Elsevier.

• Chapter 4 The Study of Risk Factors and Causation
• Chapter 5 Common Research Designs and Issues in Epidemiology