Todd-- I have done lots of license plate OD work in the early 1990s and then managed a contract for an external survey around 1997. For the external it was tricky because we had to deal with several states when it came to license plate matching. Each state had different rules and each introduced methodological concerns. Running down the line, in Illinois we at CATS bought the files from the state and did the matching ourselves. We had a lot experience with the files. In Wisconsin our consultant got the files from the state. did the matching and it was relatively easy. In Indiana the consultant was supposed to get the files but I had to get involved as the public agency and got through a process where Indiana did the matching and sent address files to us that then needed processing. The bottom line is that it was a mixed bag but dealing with multi states does take planning time. In general, external surveys are not easy and the real work is done in the planning stage. If you get close to work and want to know whats going on you will certainly have heartburn. However, if you hire someone and don't look too closely you will get fine data set. I probably got to close to mine.... Todd Ashby wrote: