From the Test 3 paper (2000), one of the questions asked what the problems were with an investigation of mortality by occupation. One of the answers in the memo was given below:
"Census/death register investigations have severe limitations and the alternative approach, through longitudinal studies, following up a group of workers in one particular industry may produce better results in the longer term. This type of investigation would embrace not just mortality, but also sickness absence which occurs nearer the onset of occupational influence on health"
I understand that introducing census every year is very costly (hence making it limited) and it could be better to track a group of individuals and see what the mortality is in that particular group. However, I am not sure what the last sentence in the memo's answer is trying to convey. Is it trying to say that we could also get morbidity rates from this new approach?