Hello. I am hoping someone will be willing to help me understand something about hazard plots created with muhaz(...). I have some background in statistics (minor in grad school), but I haven't been able to figure one thing about hazard plots. I am using hazard plots to track customer cancellations. I figure I can treat a cancellation as a "death", and if someone is still a customer today, they're right censored. I know that a hazard plot shows the probability that someone will cancel in month n given that they're a customer in month n-1 .
If a customer signs up on January 1st and cancels on January 2nd, we've had what I thought was an intellectual but pointless debate about whether we count that as being a customer for 1 month or 0 months. I thought the two plots would be identical, except for a different X axis. However, when I create the two plots, they are very different ... very, very different. I've posted the two plots to Flickr: http://flickr.com/photos/alancox/2720915878/in/photostream/ shows the plot where the lifetime of a customer who signs up on Jan 1 and cancels on Jan 2 is 0. http://flickr.com/photos/alancox/2720915904/in/photostream/ shows the plot where the lifetime of a customer who signs up on Jan 1 and cancels on Jan 2 is 1. My question is: Why are these two so different? How do I know which is right? The call that I'm making to produce the model is: hazardV08 <- muhaz(nmc,s,max.time=max(nmc)) -- Alan Cox Director, User Experience iContact, Corp. p 919.459.1038 f 919.287.2475 ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
