-
Latest posts by T
Subject Views Posted 1855 11-18-2011 03:24 PM 2101 11-17-2011 02:45 PM 2067 02-26-2010 10:31 AM 2776 02-08-2010 10:14 AM 2776 02-03-2010 05:56 AM 2794 01-29-2010 07:41 AM 2084 11-16-2009 01:02 PM -
Activity Feed for T
- Posted PROC LIFETEST survival curve template: modified strata labels on Statistical Procedures. 11-18-2011 03:24 PM
- Posted PROC LIFETEST survival curve template: modified strata labels on Statistical Procedures. 11-17-2011 02:45 PM
- Posted Re: Aggregate option changes Full Log Likelihood in PROC GENMOD on Statistical Procedures. 02-26-2010 10:31 AM
- Posted Re: INITIAL option and BY statements in GENMOD procedure on Statistical Procedures. 02-08-2010 10:14 AM
- Posted Re: INITIAL option and BY statements in GENMOD procedure on Statistical Procedures. 02-03-2010 05:56 AM
- Posted INTERCEPT option and BY statements in GENMOD procedure on Statistical Procedures. 01-29-2010 07:41 AM
- Posted Aggregate option changes Full Log Likelihood in PROC GENMOD on Statistical Procedures. 11-16-2009 01:02 PM
11-18-2011
03:24 PM
I see. It was helpful to actually have a look at the data that is passed to the plotting procedure. Like you point out, I see now that this won't allow me to add the original labels using a modified template, since the original labels are not to be found in there. I suppose it's not possible then to modify or create new input data using statements within a template, not even temporary variables (I guess this is a bit of a newbie-question)? Oh, well. I guess I'll have to write a macro for manual plotting using SGPLOT then. And I think this was the paper you were referring to. http://support.sas.com/resources/papers/proceedings11/281-2011.pdf Thanks for your reply!
... View more
11-17-2011
02:45 PM
Hi, It seems that when I'm using PROC LIFETEST to create a survival plot with number-at-risk printed on the x-axis, that whenever at least one stratum label is more than 3 characters the number-at-risk labels are printed as 1, 2, etc instead of the full strata format labels, while the strata names are printed as "1: [Label stratum 1]", "2: [Label Stratum 2]", etc. in legends (with the corresponding labels of each stratum instead of the bracketed text). See the attached file for an example (created using non-sensical data). I've been trying to get around this by modifying the template used to create the plots (Stat.Lifetest.Graphics.ProductLimitSurvival) to force the procedure to always print the full label (some additional tweaking will of course be necessary for long format labels), but I can't seem to get very much further at the moment. From what I can tell, the names to print in the figure are actually created before the template is called, since the parts of the plotting statements which hold the labels in question are never declared in the template. These include STRATUM (seems to hold stratum labels), and CLASSATRISK (seems to hold the number-at-risk labels). Is there any way to figure out where these undeclared variables come from? If not, is there any simpler way to do what I want?
... View more
02-26-2010
10:31 AM
Hi again,
I haven't replied to this in quite a long time, but I just got a similar issue with GENMOD that I want to ask about. Thanks for the reply, Dave.
But first things first: I still don't quite follow how I would go about in order to request the Deviance and Pearson's Chi-square statistics that was printed by default in earlier releases but are not in v9.2, i.e. the goodness-of-fit statistics that compare the fitted model versus the full perfect-fit model (the model with one parameter per observation). I take it this should be what I get when I specify the AGGREGATE option without a variable list?
The new issue that I have noticed is that specifying the AGGREGATE option can lead to problems of non-convergence. How come? Does this option affect the model fitting algorithm?
... View more
02-08-2010
10:14 AM
Hi again,
I had a reply from the SAS Support. Apparently this is a known limitation with GENMOD, which they hope to fix in the next version.
Until then, I guess the WHERE statement is an acceptable work-around.
... View more
02-03-2010
05:56 AM
I've reported to the SAS Support now, so we'll see if they have a solution. Thanks for your reply.
... View more
01-29-2010
07:41 AM
I'm using the BY statement to have split calculations for various groups in the same dataset, but when I specify initial values for the intercept estimate in PROC GENMOD (INTERCEPT option to the MODEL statement), only the first of the BY-groups uses the initial value. Is there any way to give an initial value for each BY-group?
Edit: Confused INITIAL and INTERCEPT options in original post.
Message was edited by: T
... View more
11-16-2009
01:02 PM
I've just upgraded from SAS v9.1 to v9.2, and noticed the nice addition of AIC and other information criteria in the GENMOD procedure Goodness-of-fit output. However, I also noticed that the Deviance and Pearson Chi-square are not printed by default, but must be requested by the AGGREGATE option to the MODEL statement.
The trouble is, for some reason that I don't quite understand, that when I leave the AGGREGATE option out, the Full Log Likelihood statistic becomes equal to the Log Likelihood, but when I give the AGGREGATE option the Full Log Likelihood statistic changes -- and consequently the AIC which is calculated from this (identical output in all other respects).
As an example, the Goodness-of-fit output from two identical models (dist=bin,link=logit), save for the aggregate option. Note in particular the change in Full Log Likelihood.
Without AGGREGATE option:
Criterion DF Value Value/DF
Log Likelihood -383.3357
Full Log Likelihood -383.3357
AIC (smaller is better) 770.6714
AICC (smaller is better) 770.6818
BIC (smaller is better) 780.7907
With AGGREGATE option:
Criterion DF Value Value/DF
Deviance 1082 722.9896 0.6682
Scaled Deviance 1082 722.9896 0.6682
Pearson Chi-Square 1082 1067.9233 0.9870
Scaled Pearson X2 1082 1067.9233 0.9870
Log Likelihood -383.3357
Full Log Likelihood -372.1276
AIC (smaller is better) 748.2552
AICC (smaller is better) 748.2655
BIC (smaller is better) 758.3744
All other output is identical. Should these values not be the same?
... View more