Wednesday, August 25, 2010
main effect of a continous variable
In both proc mixed and glimmix (see the code example below), the "Solution for Fixed Effects" generated by option /SOLUTION for the continous variable 'binary' does not estimate the main/marginal effect when the value of binary changes from 0 to 1. It is because of the interaction term between binary and visit. To find the main/marginal effect, we can code the variable 'binary' as a class/categorical variable and find this LSMEANS.
Wednesday, July 28, 2010
Wednesday, June 23, 2010
Friday, June 18, 2010
Thursday, May 20, 2010
Thursday, May 13, 2010
matching program
Case control matching, probably implementing the idea of propensity scores
R
matchIT
Matching
optmatch optmatch presentation1; optmatch presentation2;
SAS
gmatch,vmatch,dist
a sugi paper 165-29: Performing a 1:N Case-Control Match on Propensity Score
PaperOn the Estimation and Use of Propensity Scores in Case-Control and Case-Cohort Studies
[using] cases plus controls in a case-control study... should give consistent estimates of the true propensity score under the null hypothesis, but not otherwise.
R
matchIT
Matching
optmatch optmatch presentation1; optmatch presentation2;
SAS
gmatch,vmatch,dist
a sugi paper 165-29: Performing a 1:N Case-Control Match on Propensity Score
PaperOn the Estimation and Use of Propensity Scores in Case-Control and Case-Cohort Studies
[using] cases plus controls in a case-control study... should give consistent estimates of the true propensity score under the null hypothesis, but not otherwise.
Tuesday, May 11, 2010
good clinical trial simulation practices
http://cdds.ucsf.edu/research/sddgpreport.php#_Toc457223476
Monday, May 10, 2010
A Draft Sequence of the Neandertal Genome.
http://www.researchblogging.org/post/gotourl/id/213933
http://www.researchblogging.org/post/gotourl/id/213689
http://www.researchblogging.org/post/gotourl/id/213509
http://www.researchblogging.org/post/gotourl/id/213689
http://www.researchblogging.org/post/gotourl/id/213509
Viagra could help women too
http://www.helenjaques.co.uk/blog/2010/viagra-breast-cancer-drug-delivery/?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+Insicknessandinhealth+%28In+sickness+and+in+health%29
Researchers in California have shown that sildenafil (Viagra) and a similar drug called vardenafil can improve the delivery of the chemotherapeutic drug Herceptin (trastuzumab) in women with breast cancer that has spread to the brain.
Researchers in California have shown that sildenafil (Viagra) and a similar drug called vardenafil can improve the delivery of the chemotherapeutic drug Herceptin (trastuzumab) in women with breast cancer that has spread to the brain.
PubMed vs. Google Scholar
http://www.researchblogging.org/post/gotourl/id/214477
http://neurodojo.blogspot.com/2010/05/pubmed-vs-google-scholar.html?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+Neurodojo+%28NeuroDojo%29
http://neurodojo.blogspot.com/2010/05/pubmed-vs-google-scholar.html?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+Neurodojo+%28NeuroDojo%29
Antidepressants Not Effective for Some Types of Depression
http://www.researchblogging.org/post/gotourl/id/214478
http://brainblogger.com/2010/05/10/antidepressants-not-effective-for-some-types-of-depression/
http://brainblogger.com/2010/05/10/antidepressants-not-effective-for-some-types-of-depression/
Friday, April 30, 2010
Biomarkers and surrogate endpoints
A good article discussing surrogate endpoints and the gap between scientific theory and clinical benefit.
Friday, April 09, 2010
Kendall/Spearman rank correlation
copied from here.
Spearman's rho comes from Charles Spearman's background of psychology, IQ testing and eugenics - it's an easy to calculate robust measure of whether there is an association.
Spearman's rho comes from Charles Spearman's background of psychology, IQ testing and eugenics - it's an easy to calculate robust measure of whether there is an association.
Saturday, March 27, 2010
Stuart-Maxwell test
a generalization of McNemar's test for matched pair data with more than two possible outcomes. A sas macro is available here. Maybe TDT can be/have been extended in the same way.
Wednesday, February 10, 2010
survival
http://www.mail-archive.com/nmusers@globomaxnm.com/msg00398.html
COX Proportional Hazard Model with Time Dependent Covariate
COX Proportional Hazard Model with Time Dependent Covariate
Subscribe to:
Posts (Atom)