Example of intrasubject variation

The following is an example of intrasubject variation: 0 One physician might read the same x-ray film and make a different diagnosis in the morning after a good night sleep versus after 24 hours on-call in the ER. 0 Two different physicians might make different diagnoses based on the same x-ray due to subjective differences. 0 A research subject might have lower blood pressure in the morning after sleep than after running around a track. 0 Two different research subjects of the same gender and age might have different blood pressure measures due to other genetic and lifestyle differences. 0 A patient might desire to seek a second opinion after initial diagnosis with a disease.

If I wanted to measure the risk of a disease, that is the rate at which people move from an at-risk state to a

diseased state, I would calculate: O Prevalence O Positive Predictive Value O Case-Fatality Rate O

Incidence O A and D

If I wanted to measure the burden of a disease in a population at a particular point of time, I would calculate:

0 Prevalence 0 Incidence 0 Crude Mortality Rate 0 Proportionate Mortality Rate 0 Population-specific

mortality rate