Maximin Efficiencies under Treatment-Dependent Costs and Outcome Variances for Parallel, AABB, and ABBA Designs
Author
Source
Computational and Mathematical Methods in Medicine
Issue
Vol. 2018, Issue 2018 (31 Dec. 2018), pp.1-15, 15 p.
Publisher
Hindawi Publishing Corporation
Publication Date
2018-10-01
Country of Publication
Egypt
No. of Pages
15
Main Subjects
Abstract EN
If there are no carryover effects, AB/BA crossover designs are more efficient than parallel (A/B) and extended parallel (AA/BB) group designs.
This study extends these results in that (a) optimal instead of equal treatment allocation is examined, (b) allowance for treatment-dependent outcome variances is made, and (c) next to treatment effects, also treatment by period interaction effects are examined.
Starting from a linear mixed model analysis, the optimal allocation requires knowledge on intraclass correlations in A and B, which typically is rather vague.
To solve this, maximin versions of the designs are derived, which guarantee a power level across plausible ranges of the intraclass correlations at the lowest research costs.
For the treatment effect, an extensive numerical evaluation shows that if the treatment costs of A and B are equal, or if the sum of the costs of one treatment and measurement per person is less than the remaining subject-specific costs (e.g., recruitment costs), the maximin crossover design is most efficient for ranges of intraclass correlations starting at 0.15 or higher.
For other cost scenarios, the maximin parallel or extended parallel design can also become most efficient.
For the treatment by period interaction, the maximin AA/BB design can be proven to be the most efficient.
A simulation study supports these asymptotic results for small samples.
American Psychological Association (APA)
Candel, Math J. J. M.. 2018. Maximin Efficiencies under Treatment-Dependent Costs and Outcome Variances for Parallel, AABB, and ABBA Designs. Computational and Mathematical Methods in Medicine،Vol. 2018, no. 2018, pp.1-15.
https://search.emarefa.net/detail/BIM-1132195
Modern Language Association (MLA)
Candel, Math J. J. M.. Maximin Efficiencies under Treatment-Dependent Costs and Outcome Variances for Parallel, AABB, and ABBA Designs. Computational and Mathematical Methods in Medicine No. 2018 (2018), pp.1-15.
https://search.emarefa.net/detail/BIM-1132195
American Medical Association (AMA)
Candel, Math J. J. M.. Maximin Efficiencies under Treatment-Dependent Costs and Outcome Variances for Parallel, AABB, and ABBA Designs. Computational and Mathematical Methods in Medicine. 2018. Vol. 2018, no. 2018, pp.1-15.
https://search.emarefa.net/detail/BIM-1132195
Data Type
Journal Articles
Language
English
Notes
Includes bibliographical references
Record ID
BIM-1132195