Randomization Does Not Help Much, Comparability Does.
According to R.A. Fisher, randomization "relieves the experimenter from the anxiety of considering innumerable causes by which the data may be disturbed." Since, in particular, it is said to control for known and unknown nuisance factors that may considerably challenge the validity of a re...
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| Format: | Article |
| Language: | English |
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Public Library of Science (PLoS)
2015-01-01
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| Series: | PLoS ONE |
| Online Access: | http://europepmc.org/articles/PMC4507867?pdf=render |
| _version_ | 1818019186565185536 |
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| author | Uwe Saint-Mont |
| author_facet | Uwe Saint-Mont |
| author_sort | Uwe Saint-Mont |
| collection | DOAJ |
| description | According to R.A. Fisher, randomization "relieves the experimenter from the anxiety of considering innumerable causes by which the data may be disturbed." Since, in particular, it is said to control for known and unknown nuisance factors that may considerably challenge the validity of a result, it has become very popular. This contribution challenges the received view. First, looking for quantitative support, we study a number of straightforward, mathematically simple models. They all demonstrate that the optimism surrounding randomization is questionable: In small to medium-sized samples, random allocation of units to treatments typically yields a considerable imbalance between the groups, i.e., confounding due to randomization is the rule rather than the exception. In the second part of this contribution, the reasoning is extended to a number of traditional arguments in favour of randomization. This discussion is rather non-technical, and sometimes touches on the rather fundamental Frequentist/Bayesian debate. However, the result of this analysis turns out to be quite similar: While the contribution of randomization remains doubtful, comparability contributes much to a compelling conclusion. Summing up, classical experimentation based on sound background theory and the systematic construction of exchangeable groups seems to be advisable. |
| first_indexed | 2024-04-14T07:48:52Z |
| format | Article |
| id | doaj.art-7cb9f7e5bf474c94bd46e89388386d08 |
| institution | Directory Open Access Journal |
| issn | 1932-6203 |
| language | English |
| last_indexed | 2024-04-14T07:48:52Z |
| publishDate | 2015-01-01 |
| publisher | Public Library of Science (PLoS) |
| record_format | Article |
| series | PLoS ONE |
| spelling | doaj.art-7cb9f7e5bf474c94bd46e89388386d082022-12-22T02:05:15ZengPublic Library of Science (PLoS)PLoS ONE1932-62032015-01-01107e013210210.1371/journal.pone.0132102Randomization Does Not Help Much, Comparability Does.Uwe Saint-MontAccording to R.A. Fisher, randomization "relieves the experimenter from the anxiety of considering innumerable causes by which the data may be disturbed." Since, in particular, it is said to control for known and unknown nuisance factors that may considerably challenge the validity of a result, it has become very popular. This contribution challenges the received view. First, looking for quantitative support, we study a number of straightforward, mathematically simple models. They all demonstrate that the optimism surrounding randomization is questionable: In small to medium-sized samples, random allocation of units to treatments typically yields a considerable imbalance between the groups, i.e., confounding due to randomization is the rule rather than the exception. In the second part of this contribution, the reasoning is extended to a number of traditional arguments in favour of randomization. This discussion is rather non-technical, and sometimes touches on the rather fundamental Frequentist/Bayesian debate. However, the result of this analysis turns out to be quite similar: While the contribution of randomization remains doubtful, comparability contributes much to a compelling conclusion. Summing up, classical experimentation based on sound background theory and the systematic construction of exchangeable groups seems to be advisable.http://europepmc.org/articles/PMC4507867?pdf=render |
| spellingShingle | Uwe Saint-Mont Randomization Does Not Help Much, Comparability Does. PLoS ONE |
| title | Randomization Does Not Help Much, Comparability Does. |
| title_full | Randomization Does Not Help Much, Comparability Does. |
| title_fullStr | Randomization Does Not Help Much, Comparability Does. |
| title_full_unstemmed | Randomization Does Not Help Much, Comparability Does. |
| title_short | Randomization Does Not Help Much, Comparability Does. |
| title_sort | randomization does not help much comparability does |
| url | http://europepmc.org/articles/PMC4507867?pdf=render |
| work_keys_str_mv | AT uwesaintmont randomizationdoesnothelpmuchcomparabilitydoes |