Indicate the one major type of limitation that is possible in each of the situat
ID: 3309779 • Letter: I
Question
Indicate the one major type of limitation that is possible in each of the situations described below.
Choose from the following: selection bias, information bias, confounding, random error, or no error.
Choose only one per example.
1) A recent newspaper article in India Today claimed that 10% of Indian males could be impotent. These conclusions were based on a survey of 1,500 men done in Delhi by the Alpha One Andrology Center at Aashlok Hospital. All of the men surveyed were outpatients at the Andrology Center.
2) In a study of AIDS and oesophageal candidiasis, exposed participants with AIDS are compared to a group of unexposed persons without a diagnosis of AIDS on their respective frequencies of oesophageal candidiasis. The presence of oesophageal candidiasis is assessed by questionnaire, and no association is found (OR = 1.1). However, in a different study, oesophageal candidiasis was ascertained by biopsy, yielding an OR of 8.4.
3) Given that the risk of coronary heart disease increases with age, a cohort study of the association between physical activity and coronary heart disease was conducted in which the average age of the physically active group is 10 years younger than the average age of the inactive group.
Explanation / Answer
1) selection bias. Selection bias is the bias introduced by theselection of individuals, groups or data for analysis in such a way that proper randomization is not achieved. Here only males from Delhi are selected and it doesnt represent the entire country
2) Since the difference is huge in both test, this must be an information error. Information bias happens when key information is either measured, collected, or interpreted inaccurately.
3) Confounding as there is another variable which can affect the dependent variable and ideally it should be controlled for while conducting the experiment