Percentile rank confidence limits reflecting measurement error for the WAIS-III an WISC-IV

Programs: WAIS3_PRCLME.exe and WISC4_PRCLME.exe

These programs for PCs accompany the paper : Crawford, J. R. & Garthwaite, P.H. (2009). Percentiles please: The case for expressing neuropsychological test scores and accompanying confidence limits as percentile ranks. The Clinical Neuropsychologist, 23, 193-204.

Some neuropsycholgists have argued that percentiles have no role in the interpretation of test scores (e.g., Bowman, 2002) and have described them as "perfidous". In contrast, the above paper argues that percentiles should occupy a central role. That is, we suggest that neuropsychological test scores should routinely be expressed not only in derived score units (e.g., on an IQ / Index score metric) but also as percentiles. Furthermore, confidence limits that capture the uncertainty arising from measurement error on test scores are usually expressed only in derived score units; we suggest that also expressing the upper and lower limits in the form of percentiles has a number of advantages. Two programs accompany the paper:

The program WAIS3_PRCLME.exe provides percentile rank confidence limits for Index scores on the WAIS-III (confidence limits are also expressed on an Index score metric). A companion program (WISC4_PRCLME.exe) does the same for WISC-IV Index scores.  Click here to download WAIS3_PRCLME.exe, and here to download WISC4_PRCLME.exe.

Alternatively both files can be downloaded as a zip file (; 451 Kb); click here to download zip file.

Your web browser is most probably configured to recognise that the files are executables. If you have any problems (i.e. the browser treats them as text files), hold down the shift key when clicking. If your network does not allow downloads of executables then downloading the zip file is a solution.

Once downloaded, the programs can be run by any of the normal Windows procedures i.e. by clicking on file in File Manager or by placing on desktop etc.

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The author of this software (John R Crawford) and the University of Aberdeen make no representations about the suitability of the software or about any content or information made accessible by the software, for any purpose.

The software is provided 'as is' without express or implied warranties, including warranties of merchantability and fitness for a particular purpose or noninfringement.

The software is provided gratuitously and, accordingly, the author shall not be liable under any theory or any damages suffered by you or any user of the software.

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