Thanks for your reply.

Actually, I'm confused about the results in the article "Postoperative
nomogram for survival of patients with retroperitoneal sarcoma treated with
curative intent"
http://annonc.oxfordjournals.org/cgi/content/abstract/mdp298v1

It stated as:

nomogram model
The Cox model was used as the basis for the nomogram
(Table 2). Figure 2 depicts the final nomogram and portrays the
association between each variable and survival based on the
scoring system derived from this analysis. The concordance
index (discrimination) after internal validation with 200
bootstrapping resamples was 0.73 (95% CI 0.71–0.75).
Similarly, Figure 3 illustrates the calibration of the nomogram
before and after internal validation with bootstrapping samples.
Calibration was excellent with observed outcomes always
within 95% CI of the predicted survival probability.

Figure 3 is
http://i3.6.cn/cvbnm/a9/c8/8b/c01aad248a0b4ae6ef677600614bd4fa.jpg


2009/7/26 Frank E Harrell Jr <f.harrell@vanderbilt.edu>
>
> zhu yao wrote:
>>
>> Dear experts:
>>
>> I am a newbie to R. Recently, I try to make prediction models with R and
the
>> Design library.
>> I have read Prof. Harrell's excellent book. But I did not quite
understand.
>> I have two problems about the validation and calibration of prediction
>> models:
>> 1. Can someone explain the results outputted by the validate() function?
How
>> to get 95% of c-value of validate?
>
> validate does not provide that confidence interval, unfortunately.
>
>> 2. How to add 95% ci in the calibration plot?
>
> That is not provided except for survival models.
>
> Next time please include your code so we can see what model you are using.
>
> Thanks
> Frank
>
>>
>> Yao Zhu
>> Department of Urology
>> Fudan University Shanghai Cancer Center
>>
>>        [[alternative HTML version deleted]]
>>
>> ______________________________________________
>> R-help@r-project.org mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>>
>
>
> --
> Frank E Harrell Jr   Professor and Chair           School of Medicine
>                     Department of Biostatistics   Vanderbilt University

	[[alternative HTML version deleted]]


