Bayesian sample size / PropMisclassSampleSize
PropMisclassSampleSize
Bayesian sample size determination for prevalence and diagnostic studies in the absence of a gold standard



Install Instructions
PropMisclassSampleSize was developed to estimate sample size in the context of prevalence and diagnostic test studies, along the lines of our paper

Bayesian Sample Size Determination for Prevalence and Diagnostic Test Studies in the Absence of a Gold Standard Test
Nandini Denukuri, Elham Rahme, Patrick Bélisle and Lawrence Joseph
Biometrics 60, pp. 388-397
June 2004

We recommend that you read this paper carefully before using this software.

The three free software packages listed below must be installed on your computer to use PropMisclassSampleSize: All packages install easily in a few minutes.

Microsoft Windows Script is also necessary but should already be sitting on your computer if you have a recent Windows operating system
(search for wscript.exe on your computer; if you can't find it, download it from the download section of Microsoft Windows Script webpage).

Once you have installed the necessary software, PropMisclassSampleSize is ready to run; see Instruction Manual for detailed instructions.

On first use, PropMisclassSampleSize will present a graphical user interface asking you to point to the most recent locations of executable files R.exe and WinBugs*.exe. Whenever possible, paths to the R and WinBugs executable files will be displayed as default values that you might want to use if they are indeed the most recent; if not, a browse button will allow you to indicate the actual executable files to use. Program may be slow to start when first run.


Avoiding trap errors from permission settings on Windows 7 and Windows Vista platforms
If you are working on a Windows 7 or Windows Vista platform and have run WinBUGS before, y ou may have already run into the cryptic Trap #060 error message illustrated to the right. This is due to restricted write permissions in c:\Program Files, where you may have installed WinBUGS.

WinBUGS must be installed in a directory where you have write permissions (e.g. in C:\Users\user name\Documents) for PropMisclassSampleSize to run smoothly.



FAQ
When I try to run PropMisclassSampleSize, I get the message This application has failed to start because R.dll was not found. Re-installing the application may fix this problem. How can I fix it?
  1. Make sure the version for R you have installed is 2.11.1 or later;
  2. Add R bin directory to your system path, that is, through the Start menu, select Settings, then Control panel and double-click the System icon: click the Advanced tab and the Environment variables button. Scroll down the System variables list box, select Path and click the Edit button. At the end of the Variable value text box, add a semi-colon and enter the path to R bin directory, e.g. ;c:\Program Files\R\R-2.11.1\bin, and click the Ok button. Click the next few Ok buttons to exit the Control panel.