The Power of Optimization Over Randomization in Designing Experiments Involving Small Samples

Random assignment, typically seen as the standard in controlled trials, aims to make experimental groups statistically equivalent before treatment. However, with a small sample, which is a practical reality in many disciplines, randomized groups are often too dissimilar to be useful. We propose an a...

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Main Authors: Johnson, Mac, Kallus, Nathan, Bertsimas, Dimitris J
Other Authors: Massachusetts Institute of Technology. Operations Research Center
Format: Article
Language:en_US
Published: Institute for Operations Research and the Management Sciences (INFORMS) 2015
Online Access:http://hdl.handle.net/1721.1/98509
https://orcid.org/0000-0003-1672-0507
https://orcid.org/0000-0002-1985-1003
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author Johnson, Mac
Kallus, Nathan
Bertsimas, Dimitris J
author2 Massachusetts Institute of Technology. Operations Research Center
author_facet Massachusetts Institute of Technology. Operations Research Center
Johnson, Mac
Kallus, Nathan
Bertsimas, Dimitris J
author_sort Johnson, Mac
collection MIT
description Random assignment, typically seen as the standard in controlled trials, aims to make experimental groups statistically equivalent before treatment. However, with a small sample, which is a practical reality in many disciplines, randomized groups are often too dissimilar to be useful. We propose an approach based on discrete linear optimization to create groups whose discrepancy in their means and variances is several orders of magnitude smaller than with randomization. We provide theoretical and computational evidence that groups created by optimization have exponentially lower discrepancy than those created by randomization and that this allows for more powerful statistical inference.
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spelling mit-1721.1/985092023-03-01T02:14:20Z The Power of Optimization Over Randomization in Designing Experiments Involving Small Samples Johnson, Mac Kallus, Nathan Bertsimas, Dimitris J Massachusetts Institute of Technology. Operations Research Center Sloan School of Management Bertsimas, Dimitris J. Johnson, Mac Kallus, Nathan Random assignment, typically seen as the standard in controlled trials, aims to make experimental groups statistically equivalent before treatment. However, with a small sample, which is a practical reality in many disciplines, randomized groups are often too dissimilar to be useful. We propose an approach based on discrete linear optimization to create groups whose discrepancy in their means and variances is several orders of magnitude smaller than with randomization. We provide theoretical and computational evidence that groups created by optimization have exponentially lower discrepancy than those created by randomization and that this allows for more powerful statistical inference. National Science Foundation (U.S.). Graduate Research Fellowship (Grant 1122374) 2015-09-15T16:52:53Z 2015-09-15T16:52:53Z 2015-04 2014-09 Article http://purl.org/eprint/type/JournalArticle 0030-364X 1526-5463 http://hdl.handle.net/1721.1/98509 Bertsimas, Dimitris, Mac Johnson, and Nathan Kallus. “The Power of Optimization Over Randomization in Designing Experiments Involving Small Samples.” Operations Research 63, no. 4 (August 2015): 868–876. https://orcid.org/0000-0003-1672-0507 https://orcid.org/0000-0002-1985-1003 en_US http://dx.doi.org/10.1287/opre.2015.1361 Operations Research Creative Commons Attribution-Noncommercial-Share Alike http://creativecommons.org/licenses/by-nc-sa/4.0/ application/pdf Institute for Operations Research and the Management Sciences (INFORMS) MIT web domain
spellingShingle Johnson, Mac
Kallus, Nathan
Bertsimas, Dimitris J
The Power of Optimization Over Randomization in Designing Experiments Involving Small Samples
title The Power of Optimization Over Randomization in Designing Experiments Involving Small Samples
title_full The Power of Optimization Over Randomization in Designing Experiments Involving Small Samples
title_fullStr The Power of Optimization Over Randomization in Designing Experiments Involving Small Samples
title_full_unstemmed The Power of Optimization Over Randomization in Designing Experiments Involving Small Samples
title_short The Power of Optimization Over Randomization in Designing Experiments Involving Small Samples
title_sort power of optimization over randomization in designing experiments involving small samples
url http://hdl.handle.net/1721.1/98509
https://orcid.org/0000-0003-1672-0507
https://orcid.org/0000-0002-1985-1003
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