Original Articles: PDF OnlySurvival analysis: the importance of censored observationsWatt, D C2; Aitchison, T C2; MacKie, R M1; Sirel, J M2Author Information 1Department of Dermatology, Glasgow University, Glasgow G12 8QQ, UK. Fax: ( + 44) 0141 330 4814 2Department of Statistics, Mathematics Building, University of Glasgow, Glasgow G12 8QQ, UK. Fax: ( + 44) 0141 330 4814 Melanoma Research: October 1996 - Volume 6 - Issue 5 - p 379-385 Buy Abstract We have considered the issue of predicting from diagnosis of a condition such as malignant melanoma survival past an often arbitrarily chosen fixed time-point, such as 5 years. Prediction of survival past any time-point becomes rather complicated due to the presence of 'censored observations', and these observations are often ignored in any analysis. Censored observations are subjects who either die of causes other than the disease of interest or are lost to follow-up. The aim of this paper is to show that the result of ignoring these 'censored observations' is an underestimation of the probability of survival beyond the fixed time-point. Ignoring these censored observations results in potentially valuable Information on survival being thrown away. This underestimation will often prove to be of considerable magnitude and dependent on the proportion of censored observations present In the data. It is therefore essential to carry out a full actuarial survival analysis which will incorporate all the information contained in these censored observations. © Lippincott-Raven Publishers.