RE: [CTPP] New Website--Old Data

Chuck--If I understand you I could almost conclude that in the Chicago numbers that have been in play over 3 decades that we took the "place of work not reported" for our resident workers and counted them as internal flows. But that could not have happened. First the same pattern exists all the counties I checked. Cook to Cook, Dupage, Kane, Lake, Will and McHenry. The 1970 BEA numbers are low. It could be that our 1970 UTPP numbers were tweaked and if they were originally in the neighborhood of the BEA numbers I could see why. I need to check out that path as well. Chuck how do your 1970 numbers compare? Are they more in line with BEAs? Does anyone else have their 1970 CTPP numbers how do they compare? To give you an idea of magnitude here is what I am looking at for 1970. BEA----------UTPP 1,931,034----2,105,178 Cook to Cook 27,104---32624 Cook to Dupage 5,403---9,056 Cook to Kane 8,888---18,624 Cook to Lake 698---951 Cook to McHenry 3,853---4,299 Cook to Will I also have 43,076 Cook to elsewhere but I didn't add up all the BEA elsewheres. I also looked at DuPage to all the other counties and the same pattern prevailed. -------- Original Message -------- Subject: Re: [CTPP] New Website--Old Data Date: Thu, 22 Feb 2007 08:33:57 -0800 From: "Chuck Purvis" <CPurvis(a)mtc.ca.gov> To: "Ed Christopher" <edc(a)berwyned.com>,"ctpp-news maillist" <ctpp-news(a)chrispy.net> Hi Ed: The 1970 Census data on the BEA website shows a separate row, at the very end of each county's table, for "place of work not reported". So, Cook County Illinois has 181,911 resident workers with place-of-work not reported, in 1970. Part of the mystery is solved. I believe all of the "standard" 1970 Census tabulations did NOTdo place-of-work allocation (imputation), so we would always see the "not reported" data for any county, place or tract. The 1970 Urban Transportation Package (UTP) probably had some allocation (imputation) procedure to allocate the "not reported" area-of-work to whatever geographies were used after the 1970 Census. This is a guess. I don't have extensive records of the 1970 process. [I do have the "Urban Transportation Factbook" published by the American Institute of Planners and the Motor Vehicles Manufacturers Assocation, in 1974, but it appears to be based on standard census tabulations, not the UTP....?] Perhaps the answers are hidden in the Census Bureau (maybe Phil can find the info before he retires next Friday? Or perhaps the answers are in the archives - - JJ McDonnell's papers, or Alan Pisarski's office....Perhaps some information is in the TRB Special Report #145 (the 1973 Albuquerque Census conference.) Happy hunting, Chuck ************************************************************** Charles L. Purvis, AICP Principal Transportation Planner/Analyst Metropolitan Transportation Commission 101 Eighth Street Oakland, CA 94607-4700 (510) 817-5755 (office) [new, 8/1/05] (510) 817-7848 (fax) [new, 8/1/05] www: http://www.mtc.ca.gov/ Census WWW: http://www.bayareacensus.ca.gov/ ************************************************************** Our friends (who I do not know) at the Bureau of Economic Analysis who do the Regional Economic Accounts revamped their historic (1970, 1980, 1990 and 2000) Journey to Work (JTW) data base and put a nice search engine to it. For years I have sent people to the BEA sight for JTW flows but with the new search engine and the 2000 data it is so easy to use. For 2000 they have added flows by major industry at the county level and by minor industry at the state level. You really need to check it out. http://www.bea.gov/bea/regional/reis/jtw/ But then there is the nagging issue. Why do my historic CTPP/UTPP numbers and BEA not match. In 1970 and 1980 the two sources look to be off in different directions, but for 1990 they match and for 2000 it looks like a small rounding difference. Getting into the detail, attached is a comparison of the BEA/CTPP-UTPP numbers for Cook county IL, specifically the Cook to Cook flows. In 1980 BEA is about 2K higher out of 2M, but in 1970 BEA is in the neighborhood of 200K low. I know this keeps coming up, but why? Is the pattern the same around the country, BEA is high in 1980 and low in 1970? At some point we may need to reconcile all this and pick one series or the other. Since I have been tracking the Chicago region numbers (http://www.berwyned.com/papers/co2cochgo.pdf) for quite some time this has always been a nagging headache. How do all the numbers compare in your counties? Does anyone remember why the 70s and 80s might not match? -- Ed Christopher 708-283-3534 (V) 708-574-8131 (cell) FHWA RC-TST-PLN 19900 Governors Dr Olympia Fields, IL 60461