There has been an increasing interest in survival analysis with interval-censored data, where the event of interest (such as infection with a disease) is not observed exactly but only known to happen between two examination times. However, because so much research has been focused on right-censored data, so many statistical tests and techniques are available for right-censoring methods, hence interval-censoring methods are not as abundant as those for right-censored data. In this study, right-censoring methods are used to fit a proportional hazards model to some interval-censored data. Transformation of the interval-censored observations was done using a method called mid-point imputation, a method which assumes that an event occurs at some midpoint of its recorded interval. Results obtained gave conservative regression estimates but a comparison with the conventional methods showed that the estimates were not significantly different. However, the censoring mechanism and interval lengths should be given serious consideration before deciding on using mid-point imputation on interval-censored data.
Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:ufh/vital:11780 |
Date | January 2011 |
Creators | Gwaze, Arnold Rumosa |
Publisher | University of Fort Hare, Faculty of Science & Agriculture |
Source Sets | South African National ETD Portal |
Language | English |
Detected Language | English |
Type | Thesis, Masters, MSc (Biostatistics and Epidemiology) |
Format | 83 leaves; 30 cm, pdf |
Rights | University of Fort Hare |
Page generated in 0.0016 seconds