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Details van artikel 6 van 18 gevonden artikelen
| Titel: |
Group sequential checking of the proportional hazards assumption based on a time-dependent covariate |
| Auteur: |
Li, Zhengqing |
| Verschenen in: |
Communications in statistics |
| Paginering: | Jaargang 28 (1999) nr. 8 pagina's 1931-1943 |
| Jaar: |
1999 |
| Inhoud: |
In a comparative trial comparing two survival curves, the Cox regression model assumes that the hazard ratios for the two treatments are constant over time. Many advantages of using the Cox model depend on this assumption. In a group sequentially monitored survival trial, we also wish to test the proportional hazards assumption in addition to monitoring the treatment effect. This allows early detection of inappropriateness of the model. As for testing the treatment effect, simply repeating the tests in the fixed sample size case will increase false rejections. In this paper, we develop a group sequential method to check the proportional hazards assumption based on the well known time-dependent covariate by Cox (1972). The test statistics proposed have an independent increments structure. This allows the use of the standard group sequential methods such as the alpha-spending approach by Lan and DeMets (1983). The operating characteristics are studied by a simulation. |
| Uitgever: |
Taylor & Francis |
| Bronbestand: |
Elektronische Wetenschappelijke Tijdschriften |
Details van artikel 6 van 18 gevonden artikelen
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