search for: accrual

...lowable size specified by the user. The program calculates the average sample size at the # trial end. The adaptive design is based off of the paper by Schafer and Muller in Stats in # Med (2001). # # For now, the program assumes only one interim look that must occur BEFORE the end # of the planned accrual period. In other words, the program will only allow you to # extend the accrual, not to restart it. The program also assumes exponentially # distributed survival times. The program requires you to specify the maximum time # to which you are willing to extend the accrual period and the maximum ti...

...ample size estimate for a one arm survival trial. Below is some code I created to calculate such an estimate - perhaps it may be of some use. #cox.pow computes sample size for a one arm survival trial. med.0 is the null median #survival, med.a is the alternative median survival, a.time is the accrual time, and #f.time is the follow up (assumes constant accrual and two sided test). Approach taken #from Lawless 1982, p. 108 cox.pow<-function(med.0,med.a,a.time,f.time,alpha,beta) { #initialize number of events to 0 r<-0 #find necessary number of events while (qchisq((1-a...

...val analysis using a logrank test and I need some help properly doing this in R. Here is the information that I know: - I have 2 groups, namely HG and LG - Retrospective analysis with subjects gathered from archival data over 20 years. No new recruitment of subjects and no estimated time to target accrual and accrual rate. - Survival measured in both groups at 1 year, 3 years, 5 years. - Assume 50% survival for LG and 30% survival for HG at 5 years. - Assume a 6 month difference in overall survival to be statistically significant. - Total sample size is ~ N=500 with 15% of subjects comprising the LG...

Hi, I am trying to calculate the descretionary accruals using the bootstrapping technique with the R program, but I keep getting an error message. Previously, after typing in the command on the front sreen, R would return the output without any problems. I am now using a different dataset, and am getting the following error: Error in solve....

Hi everyone, I was wondering whether extension of the current spower function for Hmisc were existing? My current focus is to calculate sample size based on the log-rank test with more than 2 groups (with/without trend) Taking into account the loss of follow up and the accrual processes. A SPSS library (ART) is existing but can't find anything in R Any information is welcome ! Many thanks Laurent [[alternative HTML version deleted]]

I would like to do some power estimations for a log-rank two sample test and cpower seems to fit the bill. I am getting confused though by the man page and what the arguments actually mean. I am also not sure whether cpower takes into account censoring or not. Could anyone provide a simple example of how I would get the power for a set control/non-control clinical trial where censoring occurs at

I think we all know that the readability of steps isn''t great right now, and in fact there''s a very recent thread that discusses just that. It was that recent thread that prompted me to explore this a bit. The basic idea is that you define step matchers, which have a regex, and then you match step names against that regex. Kind of tough for me to explain so I''ll just

...Many would rather gripe about change than put in the work it takes to maintain the status quo. Then you get the crowd that tries to argue that we should just stay with what works, apparently under the misapprehension that staying in place is a zero-effort choice, when in reality it is at best an accrual of technical debt; the bill will come due eventually, with interest. I suspect these two groups overlap quite a lot, inconsistent though the combined position is. > the fact that some people do dislike change (a) does not > make the substantive and objective problems, in many people's v...

...ld rather gripe about change than put in the work it takes to maintain the status quo. > > Then you get the crowd that tries to argue that we should just stay with what works, apparently under the misapprehension that staying in place is a zero-effort choice, when in reality it is at best an accrual of technical debt; the bill will come due eventually, with interest. > > I suspect these two groups overlap quite a lot, inconsistent though the combined position is. > >> the fact that some people do dislike change (a) does not >> make the substantive and objective problems,...

On Oct 17, 2018, at 10:03 AM, Mark Rousell <mark.rousell at signal100.com> wrote: > > launchd is not being forced on them as systemd is in practice Try doing without launchd on macOS. If you think that?s irrelevant, count the number of MacBooks at the next FreeBSD conference you attend. For an init system to gain sufficient momentum, it must be the default, with no easy way to