Joe: In New Jersey, we have looked at a limited set of data for Jersey City, Newark, a few other areas, and NJ trips to Manhattan. One thing you may have to do is make sure you have corrected for the census coding as "0" any tract to tract movements where there are only 2 or less long form surveys returned. We found that in downtown Jersey City, if we did not do this, we lost almost 60% of the number of trips using tract to tract, especially reverse Trans-Hudson trips. There are procedures, including dividing two tables dealing with total travel time by mode that will get you the correct (at least from the census) number of JTW trips. In looking at NJ, most counties seemed to be low by about 10% compared to the census, which I understand is the normal correction that should be applied to census data since it only includes the primary or first job, and does not correct for persons not reporting to work that day. You also have a lot of business trips to areas of Manhattan for most of a week, so you will find a lot of workers coming from states outside the immediate 4 state area that commutes to Manhattan. Call me at 973-491-7751 or E-Mail me and we can give you further details. Do you have access to Part 3 tables for suburban NY to Manhattan JTW trips? -----Original Message----- From: ctpp-news-bounces(a)chrispy.net [mailto:ctpp-news-bounces@chrispy.net] On Behalf Of Murakami, Elaine Sent: Thursday, August 12, 2004 7:02 PM To: ctpp-news(a)chrispy.net Subject: [CTPP] CTPP Part 2 data for New York City The note below is from Joe Salvo, who is a very active member of the Census Bureau State Data Center (SDC) network, but not a CTPP listserv member: We have taken a close look at the counts of total workers from the 1990 and 2000 CTPP Part 2 at the Census Tract level. There seems to be an unusual amount of volatility, with double-digit percent increases and declines. (And, it is not a function of small bases, as many of the tracts showing large increases/declines have several thousand workers.) We have mapped the changes and, with the exception of two or three areas, these "ups and downs" seem almost randomly distributed. Has anyone else compared 1990 and 2000 CTPP data for small areas? Joe Salvo NYC Department of City Planning jsalvo(a)planning.nyc.gov _______________________________________________ ctpp-news mailing list ctpp-news(a)chrispy.net http://www.chrispy.net/mailman/listinfo/ctpp-news