Skip Navigation

This Article
Right arrow FREE Full Text (PDF) Freely available
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Archive
Right arrow Download to citation manager
Right arrowRequest Permissions
Right arrow Disclaimer
Google Scholar
Right arrow Articles by DeLucca, P.
Right arrow Articles by Raghavarao, D.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by DeLucca, P.
Right arrow Articles by Raghavarao, D.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?

Biostatistics 1:107-111 (2000)
© 2000 Oxford University Press

Effect of investigator bias on the significance level of the Wilcoxon rank-sum test

Paul DeLucca1 and Damaraju Raghavarao2

1 Biometrician, Merck & Co., Inc., 1 Walnut Grove Dr., Horsham, PA 19044, USA paul_ delucca{at}merck.com
2 Professor of Statistics, Temple University, Department of Statistics, Broad and Montgomery Ave., Philadelphia, PA 19122, USA v5558e{at}vm.temple.edu

When using subjective ordered categorical variables to measure the efficacy of an active treatment versus placebo in a double-blind clinical trial setting, bias may be introduced into the response variables when investigators become partially or totally unblinded to treatment assignment due to characteristic side effects. The investigators may alter the classification of a patient’s response to treatment based on perceived treatment assignment. The introduction of bias leads to a considerable increase in the actual significance level of the Wilcoxon rank-sum test.

Keywords: Clinical trial; Nominal level; Perceived groups; Subjective categorical measure


Add to CiteULike CiteULike   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us    What's this?




Disclaimer: Please note that abstracts for content published before 1996 were created through digital scanning and may therefore not exactly replicate the text of the original print issues. All efforts have been made to ensure accuracy, but the Publisher will not be held responsible for any remaining inaccuracies. If you require any further clarification, please contact our Customer Services Department.