EPIDEMIOLOGY and BIOSTATISTICS - Essay Example

Specific Tests are required more when a rare disease in question. However for such a communicable disease, early detection is a must and hence the more sensitive test i.e Test B should be chosen. 2. Physicians practising in the general community often find that on the average chronic debilitating conditions such as multiple sclerosis or connective tissue diseases lead to less disability and fewer complications than they were led to expect from reading reports in medical literature on the natural history of these conditions.

Why do you think this is the case? Ans 2. The chronic debilitating conditions mentioned in these diseases is a subjective and dependant variable concern. Multiple factors affect the incidence and complexity of the above mentioned diseases. Or it could be the case that, Medical awareness in the community is high so these conditions get cured before reaching an advance stage. Thus all this could contribute to the fact that these chronic conditions seem to occur with less disability and fewer complications than they were led to expect from reading reports in medical literature on the natural history of these conditions. 3. Surgeons at hospital A report that mortality rate at the end of one year follow up period after a coronary by-pass operation is 15%.

At hospital B the surgeons report a 1-year mortality rate of only 8% after the same procedure. What would you find out before concluding that surgeons at hospital B perform the operation with greater skill? Referral Bias is an important factor to be considered while determining the skill in the above case. A might be getting more complicated disease cases. Even for the same disease, it might get a disease in a more advanced stage. Thus even for the same number of cases, the mortality rate of the two hospitals is not comparable. 4. The following table shows data from a