Monitoring accrual rates (created 2006-05-30)

This scenario is based on real data, but has been adapted slightly to serve as an illustration of the use of control charts in monitoring a clinical trial.

Suppose a clinical trial was set up in 1997 and the goal was to recruit one patient per month over a ten year period, for a total sample size of 120 patients. Here are the dates of recruitment for the first 42 patients.

 [1] "2/26/1997" "4/4/1997"   "7/7/1997"   "7/25/1997"  "2/5/1998"
 [6] "2/15/1998" "3/6/1998"   "7/3/1998"   "8/3/1998"   "2/8/1999"
[11] "3/19/1999" "4/20/1999"  "5/29/1999"  "6/21/1999"  "7/27/1999"
[16] "9/6/1999"  "1/10/2000"  "1/11/2000"  "2/28/2000"  "3/3/2000"
[21] "4/13/2000" "5/30/2000"  "11/21/2000" "12/18/2000" "2/6/2001"
[26] "4/30/2001" "8/3/2001"   "11/20/2001" "12/3/2001"  "12/7/2001"
[31] "9/27/2002" "10/1/2002"  "2/2/2003"   "3/3/2003"   "10/31/2003"
[36] "11/4/2003" "11/11/2003" "1/5/2004"   "2/2/2004"   "4/15/2004"
[41] "5/23/2004" "6/2/2004"

This webpage was originally published at the StATS website, which is currently unavailable. There is a dispute about the ownership of these pages, so I am only able to include a brief excerpt from this page.

This work is licensed under a Creative Commons Attribution 3.0 United States License. This page was written by Steve Simon and was last modified on 2008-11-26. Need more information? I have a page with general help resources. You can also browse for pages similar to this one at Category: Accrual problems in clinical trials.