I had an interesting discussion with Alan Pisarski yesterday and wanted
to share some of it with everyone. Alan, along with other researchers
including Dowell Myers at USC, and Evelyn Blumenburg at UCLA, have examined how
time since immigration influences transit mode choice and vehicle acquisition.
First, let’s remember that there are “standard”
tables that the Census Bureau produces, and there are “custom”
tables done on commission. The 1990 and 2000 CTPP are
“custom” tabulations. The “standard” tabulations
come out BEFORE any “custom” products.
The questions on the ACS form are:
The current ACS standard products, such as profile S0502 use the
specific year in the table:
Entered 2000 or later
Entered 1990 to 1999
Entered before 1990
While this approach can be useful for cohort analysis, it is less
useful for understanding mode choice by time spent in the
One way to think about this is to consider “year of birth”
and the variable “age.” If a person is born in 1960, and is
surveyed in 2005, their age is tabulated as 45. If they are surveyed in
2010, their age is tabulated as 50. If the tabulation was by “year
of birth” they would always show up in the category “1960.”
Alan wants to make sure he gets the equivalent of CTPP2000 Table 1-020
with the ACS tabulations, and have it reported for metropolitan areas, and
aggregated by metro areas by population size. So, this is an opportunity
for me to bring up the topic of TABLE DESIGN for the next CTPP! We plan
for the first product of the next CTPP to use the first three years of ACS data
(2005/2006/2007). The tabulation will be limited to geographic units with
population over 20,000.
Also, Phil Salopek has already submitted a list of tables to be deleted
from the ACS standard set. This includes profile S0803, and tables of
travel time by marital status, travel time by educational attainment, and
travel time by household type. He also had travel time by race and
ethnicity on the list for deletions, but I asked if he could retain them as
they are useful for projects on environmental justice. IF THERE ARE
SPECIFIC TABLES (particularly those related to journey to work and vehicle
availability) that you MUST have as part of the ACS “standard” set,
please let me know ASAP, so that we can convey this to the CB.
If there are tables that you especially want for the first CTPP
product, please convey those ideas as well. On MY list for the first CTPP
product are:
County-to-County flow tabulation (total, and by means of transportation
to work)
PUMA-to-PUMA flow tabulation (total and by means of transportation to
work)
However, for flow tabulations from ACS, we need to make sure that the
workplace allocation program is in place to assign detailed workplace geocoding
to respondents who do not supply sufficient information on their ACS
form.
Finally, for those of you who do not already know, Phil Salopek will be
retiring from the U.S. Census Bureau on March 2. He has been a great help
to all of us in the transportation data community and we wish him well in his
new endeavors, and we hope that he will find a way to continue to work with us!
On behalf of the CTPP Team:
Elaine Murakami
206-220-4460