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From |
Andrea Bennett <mac.stata@gmail.com> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: st: In this particular case: should I prefer clustering or a random-effects model |

Date |
Thu, 7 Jul 2011 15:13:39 +0200 |

Thanks for the link and your help! I indeed do have a cluster-randomized design (treatment intervention was on the class level). With respect to FE. I have included fixed-effects dummies for each class. This results in dropped variables (classID dummies) and renders the treatment intervention to be insignificant. Performing a standard regression with <reg score treatment controls, cluster(classID)> is fine. Performing <xtreg score treatment controls, i(classID) mle/re> is fine too while <xtreg ... , i(classID) fe> results in dropped independent variables (which measure differences on the class level). But just from a theoretical point of view, I thought that a random effects model would be preferred because then I would treat the effects of "classID" as a random sample of the effects of all the classes in the full population. Best regards! Andrea On Jul 7, 2011, at 14:37 , Austin Nichols wrote: > f in fact you have a cluster-randomized design, you should have > calculated power (required sample size, minimum detectable effect > size, etc.) in advance assuming the analysis design (pooled, FE, > multilevel hierarchical model, etc.) to be used once data is > collected, using e.g. > http://www.urban.org/publications/1001394.html > or your own custom simulations, so you should not be designing the > analysis after the data has been collected! * * 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: In this particular case: should I prefer clustering or a random-effects model***From:*Steven Samuels <sjsamuels@gmail.com>

**Re: st: In this particular case: should I prefer clustering or a random-effects model***From:*Steven Samuels <sjsamuels@gmail.com>

**References**:**st: In this particular case: should I prefer clustering or a random-effects model***From:*Andrea Bennett <mac.stata@gmail.com>

**Re: st: In this particular case: should I prefer clustering or a random-effects model***From:*Austin Nichols <austinnichols@gmail.com>

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