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From | Roger Newson <r.newson@imperial.ac.uk> |
To | "statalist@hsphsun2.harvard.edu" <statalist@hsphsun2.harvard.edu> |
Subject | Re: st: Using -estat bootstrap- with -parmby- |
Date | Wed, 13 Apr 2011 18:21:45 +0100 |
If Graeme wants to view the bias-corrected confidence interval using -parmest-, then the solution is to use the -erows()- option of -parmest-, which creates new variables in the -parmest- output dataset containing the rows of a matrix estimation result (such as the bootstrap confidence interval). Instead of the -parmby- command, Graeme should probably type
parmest, erow(ci_bca) rename(er_1_1 bcamin95 er_1_2 bcamax95) list(parm estimate min95 max95 bcamin95 bcamax95 p ,clean noobs)
This -parmest- command uses the -erows()- option to extract the rows of the matrix -e(ci_bca)- into 2 variables in the output dataset, whose names are -er_1_1- and -er_1_2-, containing, respectively, the lower and upper BCa confidence limits. These variables are renamed (using the -rename()- option of -parmest-) to -bcamin95- and -bcamax95-, respectively, and are displayed using the -list()- option.
See the on-line help for -parmest- for more details. In particular, if you type
help parmest_resultssetsthen you will see a list of all the variables that -parmest- can create in its output dataset.
I hope this helps. Best wishes Roger Roger B Newson BSc MSc DPhil Lecturer in Medical Statistics Respiratory Epidemiology and Public Health Group National Heart and Lung Institute Imperial College London Royal Brompton Campus Room 33, Emmanuel Kaye Building 1B Manresa Road London SW3 6LR UNITED KINGDOM Tel: +44 (0)20 7352 8121 ext 3381 Fax: +44 (0)20 7351 8322 Email: r.newson@imperial.ac.uk Web page: http://www.imperial.ac.uk/nhli/r.newson/ Departmental Web page: http://www1.imperial.ac.uk/medicine/about/divisions/nhli/respiration/popgenetics/reph/ Opinions expressed are those of the author, not of the institution. On 13/04/2011 16:35, Maclennan, Graeme S. wrote:
Statalist, I would like to use -parmest- from SSC to store estimates of intraclass correlation coefficients (ICCs) and the bias-corrected and accelerated (BCa) confidence interval (CI) to create a large table (I will apply use -saving- option and concatenate when I get this problem sorted). To get at the BCa CI I need to run -estat bootstrap, bca- after -loneway-. All fine so far, but when I use -parmby- as below it seems to pick up the normal CI, not the Bca CI, even though the table that is produced in the results viewer is the correct table. I have made up an example using the auto.dta dataset to highlight this. Am I doing something silly, or missing something obvious? Graeme. ****begin******* sysuse auto, clear split make bootstrap ICC=r(rho), cluster(make1) bca idcluster(newmake1) reps(50) seed(1): loneway price newmake1 estat bootstrap, all parmby "estat bootstrap, bca", list(parm estimate min95 max95 p ,clean noobs) *******end******** The University of Aberdeen is a charity registered in Scotland, No SC013683. * * 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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