Question

WEEK 6 DISCUSSION: CAUSAL REASONING

Required Resources
Read/review the following resources for this activity:

• Textbook: Chapter 10
• Lesson
• Link (library article): Myopia and Ambient Lighting at Night
• Link (library article): Myopia and Ambient Night-Time Lighting
• Link (website): What Are Clinical Trials and Studies?
• Minimum of 1 scholarly source

Initial Post Instructions
As the text points out, causal reasoning is used in clinical studies. As a professional in the health field, you will undoubtedly be referring to cause/effect studies for the rest of your professional life. In this discussion, you are asked to expand and deepen your understanding of clinical studies.

In 1999, a study on the causes of myopia appeared in the prestigious journal Nature (Quinn). The study received wide-spread publicity in leading newspapers, such as the New York Times, and on television outlets, such as CBS and CNN. Within a year, another article in Nature followed up the 1999 study (Zadnik). The studies had dramatically different findings.

Using what you have learned from the text, as well as any other sources you may find useful (including the websites in the Required Resources), analyze and evaluate the methodology of both studies and how methodology affected the differences in how the studies were reported.

Reportage of both studies can be found with an Internet search using all of the following terms: <Philadelphia myopia night lights>

Follow-Up Post Instructions
Respond to at least two peers or one peer and the instructor. Further the dialogue by providing more information and clarification.

Writing Requirements

• Minimum of 3 posts (1 initial & 2 follow-up)
• APA format for in-text citations and list of references

Answer 1

Myopia is a common affliction (one in four adult Americans is near-sighted1), and juvenile-onset myopia is believed to be due to a combination of genetic and environmental factors2. Results from animal experiments indicate that light cycles may affect the development of myopia3, 4, and Quinn et al. claim to have extended these to humans5. They reported a strong association between childhood myopia and night-time lighting before the age of two: there were five times more children with myopia among those who slept with room lights on than in those who slept in the dark, and an intermediate number among those sleeping with a dim night-light5. However, we have been unable to find a link between night-time nursery lighting and the development of myopia in a sample of schoolchildren.

Think about this. You might, for example, explain how you came to have a broken leg (you tripped on a banana peel; it was raining; you were running, backwards). However, when you’re proposing an explanation for something about which the contributing factors are in dispute, then you are making an argument. You might argue for an economic explanation for your unhappiness (you just got fired, so you have no income, so you’re unhappy), while your friend might argue for a psychological explanation for your unhappiness (you hated your job, so you subconsciously sabotage it, all but forcing your supervisor to fire you, and now you feel guilty, and therefore unhappy, plus your board) because now you have nothing to do and that makes you unhappy too. Such causal explanations are often arguments because one is making a case for a particular cause, or set of causes, over another perhaps equally plausible cause, or set of causes.

Causal reasoning involves determining which of several possible explanations is the best account for a given phenomenon or occurrence. The issue can involve causation of a natural sciences kind (for example, biological, chemical, or physical causation) or causation of the social science kind i.e. social or psychological causation. Causation of the first kind is easier to establish because, at least in theory, all is measurable; it may be incredibly complicated, intricate, and far-reaching, but even so, we can measure the elements involved.

Establishing causation is important for several reasons first, it enables us to establish explanations. Second, it enables us to make predictions, and thus assess the various plans and policies about also the things. If causal explanations are correct our predictions will become true or our plans and policies will achieve their goals.

As with all inductive arguments, a strong causal argument is one in which the premises are true or acceptable, relevant, and sufficient. The degree of acceptability, relevance, and sufficiency affects the degree of strength. Often, additional information may increase our certainty about the conclusion; by all means, when that’s the case, identify and obtain the required additional information.

References:

Quinn, G. E., Shin, C. H., Maguire, M. G. & Stone, R. A. (1999). Myopia and ambient lighting at night. Nature, 399 (6732), 113-114. Retrieved from https://chamberlainuniversity.idm.oclc.org/login?url=https://search.ebscohost.com/login.aspx?direct=true&db=mdc&AN=10335839&site=eds-live&scope=site

Zadnik, K., Jones, L. A., Irvin, B. C., Kleinstein, R. N., Manny, R. E., Shin, J. A., & Mutti, D. O. (2000). Myopia and ambient night-time lighting. CLEERE study group. Collaborative longitudinal evaluation of ethnicity and refractive error. Nature, 404(6774), 143-144. Retrieved from https://chamberlainuniversity.idm.oclc.org/login?url=https://search.ebscohost.com/login.aspx?direct=true&db=mdc&AN=10724157&site=eds-live&scope=site