Re: [CTPP] CTPP Part 2 data for New York City

Elaine, Joe, Although it was not an in-depth view and analysis, I did undertake a quick check of employment here in the Minneapolis-St. Paul area.... more to see what was coming out of the CTPP files as compared to what we received from the state Employment Securities offices. Since we utilize the state figures and NOT the CTPP numbers, the differences have not been an issue. I can't offer much of an explanation other than to relate our own findings. In any case they did NOT seem to be random. Two checks were made. The first one was entirely with the 2000 figures. I mapped the Employment Securities numbers by TAZ and then the CTPP part 2 numbers by TAZ. In a fairly sizeable number of instances the two files were substantially different. However, the differences seem to have been off-set by combining contiguous TAZs. That is to say, one zone was under-counted by 1500, but the adjacent was over-counted by 1800. Admittedly I simply chalked up the bulk of these as being "address matching problems". Correctly or not, that was the assumption I made. Nearly all of these major differences fell into this situation. The second check was using the 1990 CTPP and 2000 CTPP figures. Sorting the set "high to low" by differences surprised me at first. The greatest gain was 13,319 employees; the next 6 TAZs showed gains from 4,000 to 5,600. Upon closer inspection they mostly proved to by TAZs where major growth actually did occur. The TAZ with the 13,000 gain was around the airport where our CTPP generated employment numbers always seemed suspect. We never use them. Why they are so far off the beam I don't know. Airports seem to be touchy, quirky activity centers. Those TAZs at the other end of the spectrum (showing major declines) appeared to be located adjacent to TAZs with major gains. Again, I chalked it up to address matching. Maybe I'm being lazy, for it could be something else! In several instances there were TAZ boundary issues that played into the mix. In a few other TAZs, there actually were major declines. For example, a rather large publishing company relocated from the inner city to a suburban location. That move did cause a big drop in employment that did NOT rebound. What came out of this review was that in the overwhelming majority of instances, mapping TAZs with major drops to those with major increases resulted in a pattern. They seemed to be contiguous to each other. For those that weren't, there were determining causes that could be identified. The TAZs were random around the region, but they affected TAZs with employment and were usually balanced out with adjacent TAZs. Maybe our region was lucky. You might want to check to see if this same pattern checks out with adjacent TAZs, if you haven't already done so. In the case of New York City, I can't imagine there being much of an address matching problem. Bob