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From |
"Tiago V. Pereira" <tiago.pereira@mbe.bio.br> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: st: Meta-analysis questions |

Date |
Fri, 24 Sep 2010 03:20:28 -0300 (BRT) |

I just would like to mention that I have done some confusion with the begg option in -metabias-. As the help file shows " graph - graph displays a Galbraith plot (the standard normal deviate of intervention effect estimate against its precision) for the original Egger test or a modified Galbraith plot of Z/sqrt(V) versus sqrt(V) for Harbord's modified test. ****There is no corresponding plot for the Peters or Begg tests.***** The message you got has nothing to do with the type of data you are dealing with. In practice, as long as the studies to be combined are not very small, I believe that both random and randomi approaches will give virtually identical results. If you are using data based on logor/selogor, I guess -metan- uses automatically randomi (or fixedi) even if you specify fixed/random. Cheers! Tiago > Dear Rui, > > 1) Yes, the default is the fixed-effect inverse variance method if your data is based on logor and selogor; typing "metan logor selogor, randomi" will give you the DerSimonian-Laird method. > > Type > > help metan > > to see the options. > > > 2) As the message says, the option begg can handle only raw data (e.g. 2x2 tables, with a b c d counts) > > Type > > help metabias > > for further information > > > 3) You need to provide more information on your data set, and how the typename variable was coded. > > Also, try the pdfs that the following link shows : > > http://tinyurl.com/342osna > > > Hope this helps. > > Tiago > > > -------------- > > Hi. I'm a new user of STATA and the meta-analysis commands and have a couple of questions... > > 1) For "metan logor selogor" command, is the default fixed effect? and if I would like to test for the DerSimonian & Laird random effects is it correct to type "metan logor selogor, random"? > > 2) I'm trying to do the command "metabias logor selogor, graph (begg)" but is giving me the following error message: > Note: data input format theta se_theta assumed. > Only Egger or Begg tests can be used with two input variables theta se_theta > r(198); > > What is causing this and how should I resolve it? > > 3) I'm trying to do the command "metafunnel logor selogor, by > (typename)" where typename is the type of different study designs but is it giving me the following error message: > Note: default data input format (theta, se_theta) assumed. > type mismatch > r(109); > > If i don't put in "by (typename)" it works fine and giving me the funnel plot. What is causing this and how should I resolve it? > > Thank you so much in advance for your guidance. > > Rui > > * * 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/

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