CTPP Update
9/28/2005
A. Distribution of Part 3 discs with CAT software and .ivt data files
We have completed our distribution of all the Part 3 discs containing the
CTPP Access Tool (CAT) software and data in that browser's .ivt format.
This included two higher-capacity CDs (VA and OH) and three DVDs (TX, CA,
and NY-NJ-PA). However, late in the distribution process some problems were
discovered in a few of the Part 3 .ivt tables, so the CDs and DVDs we have
distributed so far all contain some erroneous Part 3 data. See item B below
for an explanation of the error and information regarding a rerun of the
bad Part 3 tables.
B. Error in Part 3 tables
As noted in Clara Reschovsky's note to the CTPP listserve on 7/25/2005, an
error was discovered in some of the Part 3 tables in the .ivt format
contained on the software CDs and DVDs. The data distributed last year in
ASCII format do not contain the error. The error in the .ivt files is a
result of the vendor incorrectly reading the ASCII files into the browser's
format.
The error affects three tables in Part 3:
1) Table 3-08. Mean travel time by means of transportation to work (8) and
time leaving home to go to work (4)
2) Table 3-09. Median travel time by means of transportation to work (8)
and time leaving home to go to work (4)
3) Table 3-14. Aggregate travel time by means of transportation to work (8)
and time leaving home to go to work (4)
These three tables have been corrected and new files have been rerun by the
vendor. We are in the process of bundling the corrected tables into a small
number of Part 3 correction CDs that we will begin to distribute next
month. Therefore, all State Departments of Transportation and Metropolitan
Planning Organizations will be receiving one more CD from us, containing
the corrected .ivt format tables for Part 3. Note that the correction CDs
will also contain reruns of two other Part 3 tables, to correct an income
label problem as described in item C below.
C. Error in CAT household income labels for some variables in Parts 1, 2,
and 3
An error has been discovered in some income category labels being used in
the CAT software, affecting data in the browser for all three Parts of the
CTPP. The data have been tabulated according to the labels shown in
Appendix F of the CTPP documentation, but the CAT browser software is using
labels that show some incorrect income category breaks. The most detailed
household income variable (with 26 categories) is correct and not affected
by the error.
The variables affected are:
* Household income in 1999 (11), used in Part 1 (tables 30, 39, 75, 76, 79,
82) and Part 2 (tables 30 and 39)
* Household income in 1999 (9), used only in Part 3 (table 5)
* Household income in 1999 (5), used in Parts 1 and 2 (tables 42, 43, 44
in each part) and in Part 3 (table 7).
The Part 3 correction CDs that we will distribute in October will contain
new versions of tables 5 and 7 with corrected household income labels for
those two tables. However, we will not be producing corrected versions of
the Part 1 or Part 2 tables that contain erroneous income category labels
in the CAT software.
The correct household income labels may be found in Appendix F of the CTPP
documentation and are also shown below. The labels preceded with asterisks
below are correct and should be substituted for the incorrect labels
provided in the browser.
Household income in 1999 (11)
Total, Household income in 1999 (11)
Less than $10,000
$10,000-$14,999
***$15,000-$29,999
***$30,000-$39,999
***$40,000-$49,999
***$50,000-$59,999
$60,000-$74,999
$75,000-$99,999
$100,000-$124,999
$125,000 or more
Household Income in 1999 (9)
Total, Household income in 1999 (9)
Less than $15,000
***$15,000-$29,999
***$30,000-$39,999
***$40,000-$49,999
***$50,000-$59,999
$60,000-$74,999
$75,000-$99,999
$100,000 or more
Household Income in 1999 (5)
Total, Household income in 1999 (5)
***Less than $30,000
***$30,000-$49,999
***$50,000-$74,999
$75,000 or more
Any questions concerning these issues should be referred to Clara
Reschovsky (clara.a.reschovsky(a)census.gov) or Phil Salopek
(phillip.a.salopek(a)census.gov). Thank you.