Since the whole presentation Patricia Berglund gave on survival analysis is available at the SAS Global Forum takeout section (which I explained yesterday, you should have been paying attention), I just wanted to add a few highlights here.
1. Using PROC LIFETEST with a STRATA statements is a very dandy way to show survival curves for different ethnic groups on the same chart, thus visually checking whether the groups have different probabilities of depression over the lifespan. Of course, you can use this same method for any variable and any group, say, college graduation and social class.
2. She compared PROC SURVEYLOGISTIC and PROC SURVEYPHREG and found highly similar results. That was really interesting because it showed that, in her example, treating survival as continuous, as in the Cox model or dichotomous as in the logistic model did not produce much difference.
3. The data she used was from the National Co-morbidity Study, which was interesting to me, since I am very interested in open and semi-open data. (This is a term I just made up for data that is distributed beyond the original institution, for example, through the Inter-university Consortium for Political and Social Research.)
One value of this conference, and, in fact any conference, over just listening to the sessions on the Internet is the ability to ask questions of the presenters, or just get into a conversation with them. Dr. Berglund was incredibly patient with a long line of people who wanted to speak with her after her presentation, of which there were so many she ended up going out of the room to let the next presenter speak and then answering questions for another 20 or 30 minutes after her talk. Somehow we got off topic (yes, I know it’s hard to imagine that happening with me) , talking about open data, and she told me about the NHANES (National Health and Nutrition Evaluation Survey) data, which I did know about, but what I didn’t know was they had tutorials for using their data and just in general better documentation that made it easier to download and use. As a result, I’ll probably use this for my next middle school statistics presentation. I am happy.
Speaking of the value of conferences – for several years, I have made SAS Global Forum one of the conferences I attend each year. One reason for selecting SGF over the Joint Statistical Meetings, American Educational Research Association or some others is that it matches my personal interests better. I usually attend five or six events a year, I realize that sounds luxurious to some people but still my time and budget is not unlimited.
One reason I come to SGF instead of JSM or AERA is that SGF provides a more applied treatment of how to do statistics including an emphasis on the code. One thing I really liked about this survival analysis presentation was that she provided the code for each model and explained it statement by statement followed by the results. She did have some discussion on the major concepts in survival analysis at the beginning but it was more a very applied approach including how to set up your data. It’s not that AERA or JSM will not ever have this type of presentation, but there are varying emphases on theory, equations and code. Nothing is wrong with any of that but your choice of which to attend depends on your preference.
My personal bias is this – yes, problems can occur when you have a programmer who really does not understand even the most basic mathematics underlying the procedures, nor the theory. These people, for example, will not see a negative variance as a red flag or question that the mean score on the Beck Depression Inventory is 100. At least these people can DO SOMETHING and get output for me to look at.
A larger problem I have experienced is with very bright people who can tell me all about how to prove something Euclid proved back in a gazillion B.C. and provide citations for the most recent ten articles in academic journals on whatever the topic is but they can’t actually DO shit. Those people should go to SAS Global Forum and just sit in sessions like this without moving until the lights go out.
See what I provide here, rambling on statistics AND free career advice. You’re welcome.