Message-ID: <14D85EEE-F3FB-4CE8-B228-9D3FFB218B9B@me.com>
Date: 2015-08-05T14:32:02Z
From: Marc Schwartz
Subject: Question about survival::survfit
In-Reply-To: <CAKZWb7fzkpG3cCPD2DY6X9ZWCTMPhnRbNPoab4H7LU6G-MT13w@mail.gmail.com>
> On Aug 5, 2015, at 9:25 AM, Evan Kransdorf <evan.kransdorf at gmail.com> wrote:
>
> I am wanting to do a KM curve of two groups using survival. For some
> reason, the summary(survfit) gives me the following output:
>
>
>
> records n.max n.start events median 0.95LCL 0.95UCL
>
> VAR=N 10931 10931 10931 1646 NA NA NA
>
> VAR=Y 3452 3452 3452 906 NA NA NA
>
>
>
> I am not sure why it won?t give me median survival for each group? There
> are no NA in my data.
>
>
>
> Thanks very much
Presumably, because the survivorship function never crosses below 0.5. You may need to refresh yourself on the definition of median survival.
Plot the curves to visually confirm.
Regards,
Marc Schwartz