Drexel dragonThe Math ForumDonate to the Math Forum



Search All of the Math Forum:

Views expressed in these public forums are not endorsed by Drexel University or The Math Forum.


Math Forum » Discussions » sci.math.* » sci.math

Topic: dependent variable values missing not at random
Replies: 4   Last Post: May 2, 2009 11:57 PM

Advanced Search

Back to Topic List Back to Topic List Jump to Tree View Jump to Tree View   Messages: [ Previous | Next ]
Seth Myers

Posts: 28
Registered: 12/6/04
dependent variable values missing not at random
Posted: May 1, 2009 7:32 PM
  Click to see the message monospaced in plain text Plain Text   Click to reply to this topic Reply

Hi,

I have a data set where the response is time to residential development for tax parcels (some are not developed at all so censoring is happening) and predictors are assorted variables measured on the landscape (eg topographic slope). I would like to use this data to conduct a survival analysis. The problem is that some parcels (less that 5%) do not have data for the year of residential development, and so I cannot compute 'survival times' for them. It is likely that the earlier in time a house was built, the less likely anyone knows the date of building, and so data missing is likely nonrandom and correlated with date of building/survival time. I am most interested in testing hypotheses about parameter estimates in this case. I've read some of the literature on missing data, but the case where dependent values are missing not at random is not well covered, it seems. What are some potential ways to handle this situation? I thought of substituting in the values that would create the most bias and/or variance in the regression coefficients to set a bound. If my nulls are rejected under these conditions, then I can be fairly certain (can I put a probability on it?) that the complete data set would also reject these nulls. Any ideas? thanks, Seth



Point your RSS reader here for a feed of the latest messages in this topic.

[Privacy Policy] [Terms of Use]

© Drexel University 1994-2014. All Rights Reserved.
The Math Forum is a research and educational enterprise of the Drexel University School of Education.