We propose the SROCt package. This is a collection of simple R functions that were used for computing the time-dependant ROC curve for a prognostic marker from aggregated data (survival probabilities in strata of the marker) and from several studies.

More precisely, the cut-offs defining the strata of the marker are allowed to be different across the studies and need to be specified. The marker is assumed to be normally distributed. The survival function given the marker level is modeled with a piecewise-constant hazard function and the association of the marker is allowed to be different in each interval of time. Random effects are introduced in the models to take the inter-study variability into account. The regression coefficients are assessed by using the R package nlme. Illustrative data are provided: data from the cohort DIVAT, and data from a published meta-analysis (de Azambuja et al. 2007).

The complete manual of the package is available here.

Download the SROCt package and save the resulting file to your machine:

• Version 0.2 (2011/06/27) [unix/mac] [windows] [changelog]

Install the SROCt package:

• Mac and Linux Instructions

• Windows Instructions (you may need administrative privileges):

If you find any bugs in SROCt package, please e-mail us and we will take into acount your comments in the next version.