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From |
"Austin Nichols" <austinnichols@gmail.com> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: st: Verify randomization in a large sample |

Date |
Tue, 30 Sep 2008 22:04:59 -0400 |

José Luis Chávez Calva <josechc@gmail.com>: The only way to verify randomization is to observe the randomization mechanism. But you can check the balance by comparing means of several variables in the dataset like age, gender, language, etc. across categories. For example, if you have treatment and control groups defined by a variable t (=0 for control and =1 for treatment), you can do hotelling age gender language etc, by(t) or reg t age gender language etc to get an F test of the null that all means are the same. Assuming variances may differ, you can reg t age gender language etc, r and for alternative models you can run logit or probit instead (to get a chi2 test). Presumably, for a categorical t you could run mlogit t age gender language etc or -mprobit- assuming a specific error distribution under the null of randomization (in which case the X vars should not help you predict t). All of that is just for comparisons of means; for higher moments you will need tests of equality of distributions (e.g. -ksmirnov-) or graphical methods (e.g. -qqplot-). On Tue, Sep 30, 2008 at 8:18 PM, José Luis Chávez Calva <josechc@gmail.com> wrote: > Dear Stata users: > > I have a dataset on household income with a large number of > individuals. The set contains one variable indicating the locality > where each individual lives and another one indicating the household > to which this individual belongs to. I would like to know how to > verify randomization both at locality and household level using > several variables in the dataset like age, gender, language, etc. * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/

**Follow-Ups**:**RE: st: Verify randomization in a large sample***From:*"Kieran McCaul" <kamccaul@meddent.uwa.edu.au>

**References**:**st: Verify randomization in a large sample***From:*"José Luis Chávez Calva" <josechc@gmail.com>

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