Analysis by Categorizing or Dichotomizing Continuous Variables Is Inadvisable: An Example from the Natural History of Unruptured Aneurysms
Analysis by Categorizing or Dichotomizing Continuous Variables Is Inadvisable: An Example from the Natural History of Unruptured Aneurysms
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DOI:
10.3174/ajnr.a2425
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发表时间:
2011-03-01
影响因子:
3.5
通讯作者:
Altman, D. G.
中科院分区:
文献类型:
--
作者:
Naggara, O.;Raymond, J.;Altman, D. G.
In medical research analyses, continuous variables are often converted into categoric variables by grouping values into categories. The simplicity achieved by creating artificial groups has a cost: Grouping may create rather than avoid problems. In particular, dichotomization leads to a considerable loss of power and incomplete correction for confounding factors. The use of data-derived "optimal" cut-points can lead to serious bias and should at least be tested on independent observations to assess their validity. Both problems are illustrated by the way the results of a registry on unruptured intracranial aneurysms are commonly used. Extreme caution should restrict the application of such results to clinical decision-making. Categorization of continuous data, especially dichotomization, is unnecessary for statistical analysis, Continuous explanatory variables should be left alone in statistical models.