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From |
Nikolaos Pandis <npandis@yahoo.com> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
RE: st: Help on data analysis strategy |

Date |
Wed, 30 Jul 2008 10:20:39 -0700 (PDT) |

Dear subscribers, Thank you very much for your comments regarding my data analysis question. Best wsihes, Nikolaos Pandis --- On Tue, 7/29/08, Sven-Oliver Spieß <mail@svenoliverspiess.net> wrote: > From: Sven-Oliver Spieß <mail@svenoliverspiess.net> > Subject: RE: st: Help on data analysis strategy > To: statalist@hsphsun2.harvard.edu > Date: Tuesday, July 29, 2008, 10:06 PM > Before performing inferential analyses I find it often > helpful to plot the > data, e.g. means of the two groups over time for each of > the four outcomes. > > Also since outcomes are measured on a 6 point scale you > could consider > treating them as interval data. That would most likely be > easier for > computation and interpretation. If in doubt do both and see > if you would > come to different conclusions. If the conclusions are equal > you can use the > simpler model(s) and just add a footnote that substantially > the results are > the same even if "proper" model(s) are used.--Of > course that depends on your > audience. > > Best, > Sven-Oliver > > > > > -----Original Message----- > > From: owner-statalist@hsphsun2.harvard.edu > [mailto:owner- > > statalist@hsphsun2.harvard.edu] On Behalf Of > Lachenbruch, Peter > > Sent: Tuesday, July 29, 2008 7:51 PM > > To: statalist@hsphsun2.harvard.edu > > Subject: RE: st: Help on data analysis strategy > > > > While this may be solid advice to experienced > statisticians and Stata > > users, I would be a bit concerned about letting a > novice loose on > > GLLAMM > > - it's tough sledding for most experienced users. > > > > Tony > > > > Peter A. Lachenbruch > > Department of Public Health > > Oregon State University > > Corvallis, OR 97330 > > Phone: 541-737-3832 > > FAX: 541-737-4001 > > > > > > -----Original Message----- > > From: owner-statalist@hsphsun2.harvard.edu > > [mailto:owner-statalist@hsphsun2.harvard.edu] On > Behalf Of David Airey > > Sent: Tuesday, July 29, 2008 8:09 AM > > To: statalist@hsphsun2.harvard.edu > > Subject: re: st: Help on data analysis strategy > > > > . > > > > My text was stripped in my reply. > > > > There is a chapter (#7) in Multilevel and Longitudinal > Modeling Using > > Stata (Stata Bookstore) that describes mixed models > for ordinal data > > using the command GLLAMM from ssc. This is what you > need. > > > > -Dave > > > > > > > > > > > Dear subscribers, > > > > > > I am new to statistics and Stata, and I would > like to ask for > > > advice, if I amy, regarding the type analysis for > a clinical > > > experiment. > > > > > > We have 2 groups of patients, 30 in each group > that undergo surgery > > > and receive either standard medication or a new > medication to help > > > recovery. > > > > > > Both groups are asked 4 questions regarding for > example pain, > > > inflammation ect and they are required to give an > answer that gets a > > > score from 0 to 5. > > > All 4 questions are asked repeatedly for day0 > (before treatment) > > > day1, day2, day3, day5 and day7. > > > > > > The objective of the study is to see if there is > a difference > > > between the control and the experimental group as > determined by the > > > answers to the four questions. > > > > > > Some of the ideas I have are the following: > > > > > > 1. Perform a Mann Whitney test, ordinal data, > between the control > > > and the experimental group at each day and for > each question > > > separately. > > > > > > 2. Define an endpoint per question. For example > for the question on > > > pain define as endpoint when the answer is no > pain, and use right > > > sencoring for persistent pain after day7. Perform > a survival > > > analysis for each question and compare the > survival curves for the 2 > > > groups. > > > > > > 3. Convert to binary data, for example pain=yes > for score 1 to 5, > > > and pain= no for score 0. Perform logistic > regression and evaluate > > > the effect of treatment separately for every > question. > > > > > > Your advice would be greatly appreciated. > > > > > > I understand the above questions might be of > limited interest to > > > most subscribers but, anyways, I would like to > thank you for your > > > consideration. > > > > > > Best regards, > > > > > > Nikolaos Pandis > > > > * > > * 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/ > > * > * 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**:**RE: st: Help on data analysis strategy***From:*Sven-Oliver Spieß <mail@svenoliverspiess.net>

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