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From |
David Airey <david.airey@vanderbilt.edu> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: st: Re: RE: CASE-CONTROL STUDY |

Date |
Sun, 15 Mar 2009 12:12:57 -0500 |

. There is at that URL, optmatch2.ado and optmatch2.hlp.

-Dave ---------------------------------------------------------------------------------------- help for optmatch2 ---------------------------------------------------------------------------------------- Optimal Matching Syntax optmatch2 casecontrol varlist [if] [in] [, options ] options description

Main minc(#) Minimum control:case ratio. maxc(#) Maximum number of controls per set.

set each subject belongs to. caliper(#) Limit on acceptable matching. measure(string) Type of dissimilarity measure to use. epsilon(#) Stability constant.

match with as many controls as possible.

Description

below for more information. Options +------+

control can be mapped to 2 cases. Default value is 1.

default value is 1

fail with an error message.

optmatch2 will fail with an error message.

can, in theory, be matched to any case.

Mahalonobis distance.

Hansen and Klopfer (2006) for a discussion of this.

of controls it could match. Remarks

cases, 1 control and 1 case or 2 controls and 1 case. References

Statistics 15(3): 609-627.

84(408): 1024-1302. Author Mark Lunt, ARC Epidemiology Unit The University of Manchester

program On Mar 15, 2009, at 11:52 AM, Ishay Barat wrote:

Dear Kieran and DavidThere can be lots of arguments why one designs backwards study andnot forward one. In my case, I am responsible for a lot of patients,going through my department, and need form time to time to havequality control of our patients management. It would have been niceto have a quarter of a million $ and 3 years time to carry on astudy, but that's not reality.Sorry. And now for your question.As my objective is geriatric patients, and my data includes generalinter medicine ward cliental I like to reduce the noise younger andfar healthier patients introduces into my data.By matching some crucial parameters like age, sex, medication anddisease, I may get answers to my questions.As to my anagram. It is just for fun and nothing else. As to the reference to http://personalpages.manchester.ac.uk/staff/mark.lunt/optmatch.html I installed the files, but can not find the command in the menus. *¸..· ´¨)) -:¦:- * ¸.·´ . (( -:¦:- * Ishay * -:¦:- ´·.. ..·´ ((¸¸.·´* -:¦:- _________________________________________________________-Matching is an element of the design of a study, planned before thedata is collected, and should be done for efficiency, not control.If you already have the data, you gain nothing by matching. Youhave a sample size of 2,500. If you match these data in the wayyou have indicated, you will end up with a matched sample size of1,200. Why would you want to discard over half of your data?You should analyse the data as they are and control for age, sex,etc in the analysis.______________________________________________ Kieran McCaul MPH PhD WA Centre for Health & Ageing (M573) University of Western Australia Level 6, Ainslie House 48 Murray St Perth 6000 Phone: (08) 9224-2140 Fax: (08) 9224 8009 email: kamccaul@meddent.uwa.edu.au http://myprofile.cos.com/mccaul http://www.researcherid.com/rid/B-8751-2008 ______________________________________________Epidemiology is so beautiful and provides such an importantperspective on human life and death,but an incredible amount of rubbish is published. Richard Peto(2007)-----Original Message-----From: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Ishay BaratSent: Sunday, 15 March 2009 1:28 AM To: statalist@hsphsun2.harvard.edu Subject: st: CASE-CONTROL STUDY HELLOI've got a data set containing about 2500 patients, of which 300have myinterest (Group A).I would like to extract a sample of 900 patients (Group B) out ofthe dataset that match Group A in age, sex and some other parameters. AClassicalCase-Control study with 3 controllers for each case. Is anybody have a clue how the syntax look like?? *¸..· ´¨)) -:¦:- * ¸.·´ . (( -:¦:- * Ishay * -:¦:- ´·.. ..·´ ((¸¸.·´* -:¦:- * * 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/ * * 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/ -- No virus found in this incoming message. Checked by AVG.Version: 7.5.557 / Virus Database: 270.11.13 - Release Date:13-03-2009 00:00* * 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/

* * 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/

**References**:**st: Re: retruned r(198) in nlsur***From:*Kit Baum <baum@bc.edu>

**st: CASE-CONTROL STUDY***From:*"Ishay Barat" <i.b@dadlnet.dk>

**st: RE: CASE-CONTROL STUDY***From:*"Kieran McCaul" <kamccaul@meddent.uwa.edu.au>

**st: Re: RE: CASE-CONTROL STUDY***From:*"Ishay Barat" <i.b@dadlnet.dk>

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