[Skip to Content]
[Skip to Content Landing]
June 1977

Lost to Follow-up-Reply

Arch Ophthalmol. 1977;95(6):1082. doi:10.1001/archopht.1977.04450060169027

This article is only available in the PDF format. Download the PDF to view the article, as well as its associated figures and tables.


In Reply.–Ms Lang has made some important points. Tracing patients is in fact a difficult and time-consuming task. We are fortunate at the University of Iowa to have a very active Tumor Registry. The patients are contacted every six months the first two years and then once a year until death occurs; a death certificate is then obtained.

The number of patients "lost to follow-up" is an important factor if survival rates are calculated by the "direct method." To minimize the influence of such a source of error we used the "actuarial method." In this method, we deal with "person-years exposed to observation" rather than "persons." At present, we believe that the "actuarial method" gives a statistically better estimate of survival rates.

First Page Preview View Large
First page PDF preview
First page PDF preview