BookmarkSubscribeRSS Feed
🔒 This topic is solved and locked. Need further help from the community? Please sign in and ask a new question.
John4
Obsidian | Level 7

I'am using the PROC GENMOD like this :

PROC GENMOD DATA = LIFDAT;
CLASS MFG;
MODEL LIFETIME = MFG / DIST=GAMMA LINK=LOG TYPE3;
RUN;

but I dont understand why an estimated parameter equals zero

pic.PNG

What does it means ? can we change that ?

 

1 ACCEPTED SOLUTION

Accepted Solutions
PaigeMiller
Diamond | Level 26

In the CLASS statement you can add an option to change the parameterization of your model to the EFFECT, this may be what you are looking for.

 

class mfg/param=effect;

but please note the resulting model is the same, and the predictions are the same, just the way the model is parameterized has changed.

 

 

In this situation, you may be more interested in the LSMEANS, which sound like what you really want to look at here instead of the model effects, and the LSMEANS don't change depending on the parameterization of the model.

--
Paige Miller

View solution in original post

2 REPLIES 2
Rick_SAS
SAS Super FREQ

See "Parameterization of Model Effects" in the SAS documentation.

 

When you use a classification variable, one of the levels is redundant. In the GLM parameterization (the default for PROC GENMOD) the parameter for that level is set to zero.

PaigeMiller
Diamond | Level 26

In the CLASS statement you can add an option to change the parameterization of your model to the EFFECT, this may be what you are looking for.

 

class mfg/param=effect;

but please note the resulting model is the same, and the predictions are the same, just the way the model is parameterized has changed.

 

 

In this situation, you may be more interested in the LSMEANS, which sound like what you really want to look at here instead of the model effects, and the LSMEANS don't change depending on the parameterization of the model.

--
Paige Miller

sas-innovate-2024.png

Don't miss out on SAS Innovate - Register now for the FREE Livestream!

Can't make it to Vegas? No problem! Watch our general sessions LIVE or on-demand starting April 17th. Hear from SAS execs, best-selling author Adam Grant, Hot Ones host Sean Evans, top tech journalist Kara Swisher, AI expert Cassie Kozyrkov, and the mind-blowing dance crew iLuminate! Plus, get access to over 20 breakout sessions.

 

Register now!

What is ANOVA?

ANOVA, or Analysis Of Variance, is used to compare the averages or means of two or more populations to better understand how they differ. Watch this tutorial for more.

Find more tutorials on the SAS Users YouTube channel.

Discussion stats
  • 2 replies
  • 1260 views
  • 3 likes
  • 3 in conversation