https://communities.sas.com/t5/Statistical-Procedures/LOGISTIC-Turn-off-option/m-p/13236#M226 What the LOGISTIC procedure is saying is that you have an over-parametrized model. To fix that you either need more data (so all the combinations are represented) or fewer variables.<BR /> <BR /> If Radical is defined at any one of Abdominal, Laproscopic, or Vaginal, then just drop Radical, as you can estimate it's effect via the other parameters.<BR /> <BR /> Doc Muhlbaier<BR /> Duke Fri, 18 Feb 2011 18:56:00 GMT Doc_Duke 2011-02-18T18:56:00Z https://communities.sas.com/t5/Statistical-Procedures/LOGISTIC-Turn-off-option/m-p/13235#M225 I'm getting the following result when I do a proc logistic:<BR /> <BR /> NOTE: The following parameters have been set to 0, since the variables are a linear combination of other variables as shown.<BR /> <BR /> <BR /> radicalYes = 1 * Intercept - 1 * abdominalYes - 1 * laproscopicYes - 1 * vaginalYes<BR /> <BR /> <BR /> Is there a way that I can force it not to create this linear combination? Fri, 18 Feb 2011 18:13:56 GMT https://communities.sas.com/t5/Statistical-Procedures/LOGISTIC-Turn-off-option/m-p/13235#M225 SusieQ324 2011-02-18T18:13:56Z https://communities.sas.com/t5/Statistical-Procedures/LOGISTIC-Turn-off-option/m-p/13236#M226 What the LOGISTIC procedure is saying is that you have an over-parametrized model. To fix that you either need more data (so all the combinations are represented) or fewer variables.<BR /> <BR /> If Radical is defined at any one of Abdominal, Laproscopic, or Vaginal, then just drop Radical, as you can estimate it's effect via the other parameters.<BR /> <BR /> Doc Muhlbaier<BR /> Duke Fri, 18 Feb 2011 18:56:00 GMT https://communities.sas.com/t5/Statistical-Procedures/LOGISTIC-Turn-off-option/m-p/13236#M226 Doc_Duke 2011-02-18T18:56:00Z