Critical Reasoning

Critical Reasoning

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

Introduction 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 et al., 2000). The studies had dramatically different findings.Critical Reasoning

Initial Post Instructions Using what you have learned from the text, as well as any other sources you may find useful (including the website 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.Critical Reasoning

Textbook: Chapter 14 Lesson 1, 2 Link (library article): Myopia and Ambient Lighting at Night ( direct=true&db=mdc&AN=10335839&site=eds-live&scope=site) Link (library article): Myopia and Ambient Night-Time Lighting ( direct=true&db=mdc&AN=10724157&site=eds-live&scope=site) Link (website): What Are Clinical Trials and Studies? ( clinical-trials-and-studies) Minimum of 1 scholarly source (in addition to the textbook and noted readings)

8/15/20, 4:36 AM Page 1 of 39

” Reply

Writing Requirements Critical Reasoning

Grading This activity will be graded using the Discussion Grading Rubric. Please review the following link:

Course Outcomes (CO): 3, 4, 5

Due Date for Initial Post: By 11:59 p.m. MT on Wednesday Due Date for Follow-Up Posts: By 11:59 p.m. MT on Sunday



National Intitute on Aging. (n.d.). What are clinical trials and studies? Critical Reasoning

Quinn, G. E., Shin, C. H., Maguire, M. G. & Stone, R. A. (1999). Myopia and ambient lighting at night. Nature, 399 (6732), 113-114. url= 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. url= direct=true&db=mdc&AN=10724157&site=eds-live&scope=site

Minimum of 3 posts (1 initial & 2 follow-up) Minimum of 2 sources cited (assigned readings/online lessons and an outside source) APA format for in-text citations and list of references

Link (webpage): Discussion Guidelines Critical Reasoning

8/15/20, 4:36 AM Page 2 of 39

( Sheffield (Instructor) Jun 22, 2020

Edited by Sonja Sheffield ( on Jun 22 at 12:40pm

” Reply #

Greetings Students,

You are only required to post an initial answer post and ONE follow-up post in each required discussion, each week.

Please make your TWO posts each week between Monday and Sunday. Your posts must occur on different days with the first post occurring by Wednesday. If there are extenuating circumstances, please communicate with your professor. Critical Reasoning

For the second half of this week, this discussion is an object lesson in the necessity to give even peer-reviewed articles a close reading and close evaluation. It is glaringly obvious that the Quinn study did not control for the variable of heredity. It is also easy to overlook or misinterpret essential information when comparing the two studies. The Chapter 14 table “Steps in a Scientific Investigation” will be invaluable in guiding the discussion for this second half.

Consider the following:

Does Quinn respond to the Zadnik study? If yes, what is his response? In what respect does the Zadnik study replicate the Quinn study – how is the methodology the same? Where does it differ? Referring to the “Steps in a Scientific Investigation” table in Chapter 14, where do you see the most significant flaw in the Quinn study? The steps are numbered – refer by number to each step you think is relevant.


Monica Hernandez ( Tuesday



Good morning Professor and Class, Critical Reasoning

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

8/15/20, 4:36 AM Page 3 of 39

animal experiments indicate that light cycles may affect the development of myopia3, 4, and claim to have extended these to humans 5. 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-light. However, we have been unable to find a link between night- time nursery ( lighting and the development of myopia in a sample of school children. 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, backward). 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. Critical Reasoning

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 are 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.


Quinn, G. E., Shin, C. H., Maguire, M. G. & Stone, R. A. (1999). Myopia and ambient lighting at night. Nature, 399 (6732), 113-114. url=

Search entries or author Unread $ Critical Reasoning


& Subscribe



8/15/20, 4:36 AM Page 4 of 39

” Reply #


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. url= direct=true&db=mdc&AN=10724157&site=eds-live&scope=site ( direct=true&db=mdc&AN=10724157&site=eds-live&scope=site)

( Sheffield (Instructor) Tuesday

” Reply #


Monica, thanks for your post for this week and your thoughts on the studies performed. I am not detecting your thoughts on the methodologies of each study; what am I missing?

Identify the following argument as to type. And as best as you are able, identify the premise(s) and the conclusion.:

A recent study suggests that depression causes employees to have problems at work. Researchers compared 286 depressed workers with 193 others who were not depressed. Since only the depressed workers had such problems as fatigue, lack of motivation, and trouble managing their usual workload, researchers concluded that depression was the cause of their problems at work.

( Critical Reasoning

Caitlyn Pienkowski ( Wednesday


8/15/20, 4:36 AM Page 5 of 39

” Reply #


In the study of Myopia and Ambient Night-Time Lighting, it points out some of the differences in their study of Myopia compared to the first study done in 1999. In the second study done, they found an association between parental myopia and nursery night-time lighting suggests that Quinn et al.’s study should have controlled for parental myopia ( Zadnik, 2000). The second study had older children and had different lighting compared to the first study, which gave different results that did not replicate the first study Critical Reasoning.