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| From | jose maria pacheco de souza <jmpsouza@usp.br> |
| To | statalist@hsphsun2.harvard.edu |
| Subject | Re: st: About taking log on zero values |
| Date | Fri, 21 Feb 2014 10:22:50 -0300 |
Em 21/02/2014 10:17, Maarten Buis escreveu:
On Fri, Feb 21, 2014 at 1:53 PM, jose maria pacheco de souza wrote:It would be very useful if someone could make an organized summary of the sugestions.Nick started out with a well organized and large set of sugestions and considerations <http://www.stata.com/statalist/archive/2014-02/msg00790.html> To that I added the option of creating an indicator variable for x=0, set x at the smallest non-zero value, take the log of that x and add both the log and the indicator variable. <http://www.stata.com/statalist/archive/2014-02/msg00826.html> and that idea was independetly repeated by Daniel Feenberg <http://www.stata.com/statalist/archive/2014-02/msg00874.html>. Alternative transformations that don't have a problem with x=0 were proposed by Mark Schaffer <http://www.stata.com/statalist/archive/2014-02/msg00837.html> and Nick Cox <http://www.stata.com/statalist/archive/2014-02/msg00848.html>. Alfonso Sánchez-Peñalver suggested using Tobit or Heckman models to predict alternative values for the 0s here: <http://www.stata.com/statalist/archive/2014-02/msg00845.html>. Hope this helps, Maarten
Maarten: Very good. Thank you. josé maria -- Jose Maria Pacheco de Souza Professor Titular (aposentado), Professor Senior Departamento de Epidemiologia/Faculdade de Saude Publica, USP Av. Dr. Arnaldo, 715 01246-904 - S. Paulo/SP - Brasil fone (11)3768-8612 www.fsp.usp.br/~jmpsouza * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/faqs/resources/statalist-faq/ * http://www.ats.ucla.edu/stat/stata/