Balancing Treatment Allocation over Continuous Covariates: A New Imbalance Measure for Minimization
In many clinical trials, it is important to balance treatment allocation over covariates. Although a great many papers have been published on balancing over discrete covariates, the procedures for continuous covariates have been less well studied. Traditionally, a continuous covariate usually needs...
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| Format: | Article |
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Wiley
2012-01-01
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| Series: | Journal of Probability and Statistics |
| Online Access: | http://dx.doi.org/10.1155/2012/842369 |
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| author | Yanqing Hu Feifang Hu |
| author_facet | Yanqing Hu Feifang Hu |
| author_sort | Yanqing Hu |
| collection | DOAJ |
| description | In many clinical trials, it is important to balance treatment allocation over covariates. Although a great many papers have been published on balancing over discrete covariates, the procedures for continuous covariates have been less well studied. Traditionally, a continuous covariate usually needs to be transformed to a discrete one by splitting its range into several categories. Such practice may lead to loss of information and is susceptible to misspecification of covariate distribution. The more recent papers seek to define an imbalance measure that preserves the nature of continuous covariates and set the allocation rule in order to minimize that measure. We propose a new design, which defines the imbalance measure by the maximum assignment difference when all possible divisions of the covariate range are considered. This measure depends only on ranks of the covariate values and is therefore free of covariate distribution. In addition, we developed an efficient algorithm to implement the new procedure. By simulation studies we show that the new procedure is able to keep good balance properties in comparison with other popular designs. |
| format | Article |
| id | doaj-art-f43a175e98ac48f1a430f489b09b836f |
| institution | Kabale University |
| issn | 1687-952X 1687-9538 |
| language | English |
| publishDate | 2012-01-01 |
| publisher | Wiley |
| record_format | Article |
| series | Journal of Probability and Statistics |
| spelling | doaj-art-f43a175e98ac48f1a430f489b09b836f2025-02-03T06:13:53ZengWileyJournal of Probability and Statistics1687-952X1687-95382012-01-01201210.1155/2012/842369842369Balancing Treatment Allocation over Continuous Covariates: A New Imbalance Measure for MinimizationYanqing Hu0Feifang Hu1Department of Statistics, West Virginia University, Hodges Hall, Morgantown, WV 26506, USADepartment of Statistics, University of Virginia, Halsey Hall, Charlottesville, VA 22904, USAIn many clinical trials, it is important to balance treatment allocation over covariates. Although a great many papers have been published on balancing over discrete covariates, the procedures for continuous covariates have been less well studied. Traditionally, a continuous covariate usually needs to be transformed to a discrete one by splitting its range into several categories. Such practice may lead to loss of information and is susceptible to misspecification of covariate distribution. The more recent papers seek to define an imbalance measure that preserves the nature of continuous covariates and set the allocation rule in order to minimize that measure. We propose a new design, which defines the imbalance measure by the maximum assignment difference when all possible divisions of the covariate range are considered. This measure depends only on ranks of the covariate values and is therefore free of covariate distribution. In addition, we developed an efficient algorithm to implement the new procedure. By simulation studies we show that the new procedure is able to keep good balance properties in comparison with other popular designs.http://dx.doi.org/10.1155/2012/842369 |
| spellingShingle | Yanqing Hu Feifang Hu Balancing Treatment Allocation over Continuous Covariates: A New Imbalance Measure for Minimization Journal of Probability and Statistics |
| title | Balancing Treatment Allocation over Continuous Covariates: A New Imbalance Measure for Minimization |
| title_full | Balancing Treatment Allocation over Continuous Covariates: A New Imbalance Measure for Minimization |
| title_fullStr | Balancing Treatment Allocation over Continuous Covariates: A New Imbalance Measure for Minimization |
| title_full_unstemmed | Balancing Treatment Allocation over Continuous Covariates: A New Imbalance Measure for Minimization |
| title_short | Balancing Treatment Allocation over Continuous Covariates: A New Imbalance Measure for Minimization |
| title_sort | balancing treatment allocation over continuous covariates a new imbalance measure for minimization |
| url | http://dx.doi.org/10.1155/2012/842369 |
| work_keys_str_mv | AT yanqinghu balancingtreatmentallocationovercontinuouscovariatesanewimbalancemeasureforminimization AT feifanghu balancingtreatmentallocationovercontinuouscovariatesanewimbalancemeasureforminimization |