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Stratified multivariate Mann-Whitney estimators for the comparison of two treatments with randomization based covariance adjustment

Publication ,  Journal Article
Kawaguchi, A; Koch, GG; Wang, X
Published in: Statistics in Biopharmaceutical Research
December 1, 2011

Methodology for comparing two randomly assigned treatments for strictly ordinal response variables has been discussed throughout the literature on multivariate Mann-Whitney estimators with stratification adjustment. Although such estimators can be computed directly as weighted linear combinations of within-stratum Mann-Whitney estimators, consistent estimation of their covariance matrix is done using methods for multivariate U-statistics. The scope of these methods includes ways of managing randomly missing data and ways to invoke randomization-based covariance adjustment for no differences between treatments for background or baseline covariables. The assessment of treatment differences can be done using confidence intervals or statistical tests for the adjusted Mann-Whitney estimators. The methods in this article are illustrated using three examples. The first example is a randomized clinical trial with eight strata and a univariate ordinal response variable. The second example is a randomized clinical trial with four strata, two covariables, and four ordinal response variables. The third example is a randomized two-period crossover clinical trial with four strata, three covariables (as age, screening, first baseline), three response variables (as first period response, second baseline, second period response), and missing data. For these examples, the results are interpretable through the probability of better outcomes for one treatment over the other. © American Statistical Association Statistics in Biopharmaceutical Research.

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Published In

Statistics in Biopharmaceutical Research

DOI

EISSN

1946-6315

Publication Date

December 1, 2011

Volume

3

Issue

2

Start / End Page

217 / 231

Related Subject Headings

  • 4905 Statistics
  • 0104 Statistics
 

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Kawaguchi, A., Koch, G. G., & Wang, X. (2011). Stratified multivariate Mann-Whitney estimators for the comparison of two treatments with randomization based covariance adjustment. Statistics in Biopharmaceutical Research, 3(2), 217–231. https://doi.org/10.1198/sbr.2010.10007
Kawaguchi, A., G. G. Koch, and X. Wang. “Stratified multivariate Mann-Whitney estimators for the comparison of two treatments with randomization based covariance adjustment.” Statistics in Biopharmaceutical Research 3, no. 2 (December 1, 2011): 217–31. https://doi.org/10.1198/sbr.2010.10007.
Kawaguchi A, Koch GG, Wang X. Stratified multivariate Mann-Whitney estimators for the comparison of two treatments with randomization based covariance adjustment. Statistics in Biopharmaceutical Research. 2011 Dec 1;3(2):217–31.
Kawaguchi, A., et al. “Stratified multivariate Mann-Whitney estimators for the comparison of two treatments with randomization based covariance adjustment.” Statistics in Biopharmaceutical Research, vol. 3, no. 2, Dec. 2011, pp. 217–31. Scopus, doi:10.1198/sbr.2010.10007.
Kawaguchi A, Koch GG, Wang X. Stratified multivariate Mann-Whitney estimators for the comparison of two treatments with randomization based covariance adjustment. Statistics in Biopharmaceutical Research. 2011 Dec 1;3(2):217–231.
Journal cover image

Published In

Statistics in Biopharmaceutical Research

DOI

EISSN

1946-6315

Publication Date

December 1, 2011

Volume

3

Issue

2

Start / End Page

217 / 231

Related Subject Headings

  • 4905 Statistics
  • 0104 Statistics