Sheps, M., Mustafa, A. (1975). Some Considerations Affecting the Design of Follow-Up Studies. test, 19(2), 121-142. doi: 10.21608/esju.1975.315759
Mindel C. Sheps; Ahmed Fathy Mahmoud Mustafa. "Some Considerations Affecting the Design of Follow-Up Studies". test, 19, 2, 1975, 121-142. doi: 10.21608/esju.1975.315759
Sheps, M., Mustafa, A. (1975). 'Some Considerations Affecting the Design of Follow-Up Studies', test, 19(2), pp. 121-142. doi: 10.21608/esju.1975.315759
Sheps, M., Mustafa, A. Some Considerations Affecting the Design of Follow-Up Studies. test, 1975; 19(2): 121-142. doi: 10.21608/esju.1975.315759

Some Considerations Affecting the Design of Follow-Up Studies

The Egyptian Statistical Journal
Article 1, Volume 19, Issue 2, December 1975, Pages 121-142
Document Type: Original Article
DOI: 10.21608/esju.1975.315759
Authors
Mindel C. Sheps; Ahmed Fathy Mahmoud Mustafa
Abstract
When a reasonable basis exists for postulating the distribution of risks (or of survival times) in a population, it may also provide a basis for choosing a desirable combination of sample size (n) and duration of follow-up (t). In studies of conception risk, if a Beta distribution of risks is assumed, the asymptotic precision and bias of maximum likelihood estimators of the parameters are improved by a moderate prolongation of t. Not surprisingly, the desirable value of t increases as the mean risk decreases, i.e. as the probability of "survival" beyond a fixed t increases.
Keywords
Design of Follow; Up Studies; Survival Times; Maximum Likelihood Estimators
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