ctpp-news

ctpp-news@mailman.chrispy.net

2560 discussions

by ed christopher

Starting, October 28th and running for 4 weeks, Cynthia Taeuber is teaching an online course on "Using the Census's American Community Survey". The course costs $400 and more information can be found at. http://www.statistics.com/content/courses/census/index.html Although I have not taken the course I have used Cynthia's materials and slides in the past and found her presentations on the ACS to be most informative. If anyone signs up and takes the course I would be interested in hearing about it. -- Ed Christopher Resource Center Planning Team Federal Highway Administration 19900 Governors Drive Olympia Fields, Illinois 60461 708-283-3534 (V) 708-574-8131 (cell) 708-283-3501 (F)

20 years, 4 months

Ron Svejkovsky/PWD/COGV is out of the office.

by rsvejkovsky＠GREENVILLENC.GOV

I will be out of the office starting 09/30/2005 and will not return until 10/04/2005. I will respond to your message when I return. Thanks! *********************************************************************************** This e-mail is for the intended recipient only. If you have received it by mistake, please let us know by reply and then delete it from your system; access, disclosure, copying, distribution or reliance on any of it by anyone else is prohibited. If you as, intended recipient, have received this e-mail incorrectly, please notify the sender (via e-mail) immediately.

20 years, 5 months

RE: [Bay Area Census] American Community Survey 2004 Data is now available

by Richard Lin

Generally speaking, the ACS estimates use the FSCPE's (Federal-State Cooperation for Populatin EStimates) state and county estimates as controls but not the exact figures. It is more complicate with detailed adjustments without documented explanations. At least it happens to the 2004 ACS estimates to Colorado counties and municipalities. - Richard Lin, Ph.D. Demographer Colorado Division of Local Government (303)866-4989, fax (303)866-2660 richard.lin(a)state.co.us >>> "Chuck Purvis" <CPurvis(a)mtc.ca.gov> 9/2/2005 12:20 PM >>> Jeffrey: [I'm cross-posting my message to the national census-transportation listserv] You raise important points: 1. How does the Census Bureau weight & expand the American Community Survey? Do they weight it to match sub-county "control totals"? 2. How will formula allocation programs (HUD, HHS, DOT) utilize American Community Survey in allocating funds to local jurisdictions? How will formula allocation programs handle the higher standard errors, and confidence intervals, associated with the ACS? Answers: 1. The Census Bureau, to the best of my knowledge, uses counties as the finest geographic level for expanding and weighting ACS data. They do not use sub-county or place-level control totals (e.g., like they did with the weighting of decennial long form data to match decennial short form control totals). The "control totals" the Census Bureau uses are the state-federal cooperative population estimates program, which produces data on TOTAL population by age by sex by race/hispanic status. (How the Bureau adjusts these county-level population estimates to remove the group quarters population, I don't know.) Again, this is all to the best of my knowledge. For example, our State Department of Finance reports the population for Alameda County, in 2004, as 1,497,000. If we assume the same 1.9% of Alameda County's population of group quarters, then this means about 1,469,000 persons-in-households in Alameda County in 2004. The ACS measures 1,427,827 household persons in Alameda County, a difference of 4.7%. Why this difference? The pop estimates that the Bureau is using are perhaps different (?) than the pop estimates that the California DOF released this past May. To state that the weighting and expansion of American Community Survey data is an "issue" is a gross understatement. It's a really, really big issue. 2. In terms of the question "how will allocation formulas be affected by ACS?" This is really a very, very significant issue and honestly, I don't know. For example, the president recently signed the federal transportation reauthorization bill (SAFETEA-LU). There are two formula programs based on the distribution of DISABLED persons (for the "New Freedom Program") and the number of PERSONS BELOW THE 150% POVERTY LEVEL (for the Jobs Access-for-Reverse Commuting - - JARC Program), based on urbanized area population. Right now, the only urbanized area data on disabled population and poverty population is from the decennial census. So, to allocate data NOW, the USDOT would need to rely on Census 2000 data. When data is available from the 2005-2007 ACS (3-year accumulation of data), down to the SMALL URBANIZED AREAS (50,000 to 65,000 population), the USDOT MAY CHOOSE TO USE THE ACS 3-YEAR DATA TO ALLOCATE JARC & New Freedom funds....Hopefully the 3-year ACS data is less jumpy & jittery than the one-year data we've seen over the past four years. (An additional point to make is that the disability data from the decennial census isn't that good. The disability data from the ACS should be a much better indicator of disability levels.) The other example, probably more near and dear to city planner's hearts, is the allocation of community development block grant (CDBG) funds based on census-tract level estimates of poverty (?) population. I think the funding agency will have to at least look at using the five-year accumulation of ACS data, but I'm concerned (as are many others) about the "bright line" rules that regulate whether an area does or doesn't receive CDBG funds. [I am out of my element & comfort zone when talking about CDBG fund allocations. If there's a HUD-Census user forum that discusses these issues, that would be great information to share. Here is a link to a 2002 vintage HUD report on the ACS. I haven't read it yet: http://www.huduser.org/publications/polleg/acs.html I've heard comments from the Census Bureau folks that the ACS data is best for "characteristics, not counts" but the Bureau will need to realize that we data users want it all: both characteristics (shares, rates & proportions) and counts (# of persons below poverty level, # of disabled, # of zero-vehicle households, # of transit commuters, etc.) My strongest recommendation is to "cross-validate" the ACS data with other, local administrative data. The best cross-validation, at a city level, will be to compare the citywide total housing unit estimate from the ACS against the City's own records on total units.... This is a long-winded "I don't know" response. 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/ ************************************************************** >>> JPLevin(a)oaklandnet.com 09/01/05 6:21 PM >>> This new ACS data raises a lot of questions for us. It shows our 2004 population as 365,266 with lower/upper bounds of 338,601 and 391,931 Our 2000 population was over 399,000. Even subtracting out the 7,000 or so households in group quarters (who aren't counted in the ACS), this would give us 392,000 in 2000, but only 365,266 in 2004, despite a significant increase in our housing stock and by all indications an increase in population. Department of Finance estimate is 411,319 for 2004 and 412,318. Does anyone else have similar problems? This kind of undercounting can cost cities a LOT of money. _________________________________ Jeffrey P. Levin (jplevin(a)oaklandnet.com) Housing Policy & Programs Coordinator City of Oakland/Community & Economic Development Agency 250 Frank Ogawa Plaza, 5th Floor Oakland, CA 94612 510/238-3501 FAX: 510/238-3691 http://www.oaklandnet.com/government/hcd _______________________________________________ ctpp-news mailing list ctpp-news(a)chrispy.net http://www.chrispy.net/mailman/listinfo/ctpp-news

20 years, 5 months

Census News Brief

by Ed Christopher

October 2, 2005 CENSUS FUNDING UPDATE and more Congress took steps last week to keep the federal government running in the new fiscal year that began October 1, after failing to enact all but two of the twelve regular appropriations bills by the end of fiscal year 2005 (FY05) on September 30. The Continuing Resolution (House Joint Resolution 68) funds federal agencies through November 18, 2005 (or until a separate appropriations bill is enacted, if sooner), indicating that Congress intends to stay in session well past its original adjournment target of early October. The terms of the Continuing Resolution are not favorable for the Census Bureau in the short run. The measure temporarily funds agencies at the lower of three levels: the House-passed level, the Senate-passed level (if applicable), or the fiscal year 2005 level. Last month, the U.S. Senate allocated $727.4 million for the Census Bureau in fiscal year 2006 (FY06), an amount $17 million below the FY05 level and $80 million below the amount approved by the House of Representatives in June. The President requested $877.4 million for the agency in FY06. Data processing contract awarded: Implementation of a $500 million contract for the 2010 census data processing system, awarded last week to Lockheed Martin Corporation, could be delayed if Congress fails to appropriate more money for the Census Bureau than the amount approved by the Senate last month. Lockheed Martin coordinating a team that includes IBM, Computer Sciences Corporation, Pearson Government Solutions, and several other companies will be responsible for all systems, facilities, and staffing to process census responses reported on paper questionnaires, by telephone, and via the Internet. The six-year contract for the Decennial Response Integration System (DRIS) includes developing an Internet response option for the census, which was offered but not widely used in 2000. However, the Census Bureau warned in June that the FY06 funding level adopted by the Senate Appropriations Committee (and subsequently by the full Senate) could delay the award of the DRIS contract. The bureaus impact statement, issued June 29, says that delaying the award would postpone[e] critical efforts to ensure we can effectively integrate data capture of respondent data from multiple sources in the 2010 Census and increas[e] the likelihood that this will not be successful in 2010. The decision to award the contract before negotiators have met to decide on a final funding level could indicate that the Census Bureau is confident it will receive a much higher budget than the Senate approved; alternatively, the bureau could delay implementation of the contract if appropriators fail to allocate sufficient funds. New report explains ACS: A new report from the Washington-based Population Reference Bureau (PRB) offers a useful description of the Census Bureaus American Community Survey (ACS), with a focus on important differences between ACS and census long form methods and data. Authors Mark Mather, Kerri Rivers, and Linda Jacobsen compare data collection in the two surveys for several key socio-economic characteristics, including income and poverty, immigration and language, housing and commuting, and marriage and family relationships. The American Community Survey is available through the PRBs web site at www.prb.org (see top center of home page). New Census Advisory Committee to meet: The newly-created 2010 Census Advisory Committee will hold its first meeting on October 27-28 at Census Bureau headquarters in Suitland, MD. The committee replaced the Decennial Census Advisory Committee, which was disbanded last winter. The advisory committee will meet on Thursday, October 27, from 8:30 AM 5:15 PM, and on Friday, October 28, from 8:45 11:45 AM. Topics of discussion include updates from congressional staff; status of planning for the 2010 census, including communications plans; Master Address File and TIGER digital mapping system improvement; American Community Survey field work, including in Gulf Coast areas; and Census Bureau research related to questionnaire content and coverage improvement. The meeting will take place in the Francis Amasa Walker Conference Center at the Census Bureau (Building #3). It is open to the public. In the September 16th Census News Brief, I inadvertently neglected to include the National Conference of State Legislatures on the list of committee members. (My apologies to my good friend, Tim Storey, who has ably represented NCSL on the census advisory committee for many years!) Census News Briefs are prepared by Terri Ann Lowenthal, an independent consultant in Washington, DC, with support from The Annie E. Casey Foundation and other organizations. Ms. Lowenthal is also a consultant to The Census Project, sponsored by the Communications Consortium Media Center. All views expressed in the News Briefs are solely those of the author. Please direct questions about the information in this News Brief to Ms. Lowenthal at 202/484-3067 or by e-mail at TerriAnn2K(a)aol.com. Please feel free to circulate this document to other interested individuals and organizations. -- Ed Christopher 708-283-3534 (V) 708-574-8131 (cell) FHWA RC-TST-PLN 19900 Governors Dr Olympia Fields, IL 60461

20 years, 5 months

ACS Workplace Data

by clara.a.reschovsky＠census.gov

Transporation Data Users, The Census Bureau has provided early release of selected workplace based tables for areas affected by Hurricanes Katrina and Rita. Included in this release are the following tables: B08406. Sex of Workers by Means of Transportation for Workplace Geography, 2004 B08526. Means of Transportation to Work by Industry for Workplace Geography, 2004 B08528. Means of Transportation to Work by Class of Worker for Workplace Geography, 2004 B08534. Means of Transportation to Work by Travel Time to Work for Workplace Geography, 2004 These tables are being released for States, Counties, Places, and Metropolitan Statistical Areas for areas of 250,000 or more residents in Alabama, Arkansas, Florida, Georgia, Louisiana, Mississippi, Tennessee, and Texas. These tabulations are produced to provide estimates of workers at the location of their workplace. Estimates of counts of workers at the workplace may differ from those of other programs because of variations in definitions, coverage, methods of collection, reference periods, and estimation procedures. The ACS is a household survey which provides data that pertains to individuals, families, and households. This data for AL, LA, and MS can be found on the Hurricane Data link off the main Census page at www.census.gov or directly at http://www.census.gov/Press-Release/www/2005/katrina.htm. Currently on the Katrina tab, there is a Transporation Section which contains the Workplace tables. This site will be updated to reflect the damage done by Rita, so check back on the "Rita tab" for more information later. The complete tables can be found on AmericanFactfinder (www.factfinder.census.gov), marking the first time data tabulated at the Workplace Geography is included on American FactFinder. The remainder of the states geography will be released early next year as indicated in the current schedule for 2004 ACS data. Clara Reschovsky US Census Bureau

20 years, 5 months

Update on CTPP

by phillip.a.salopek＠census.gov

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.

20 years, 5 months

RE: [CTPP] 2004 ACS Data Release

by Thabet Zakaria

Last week, two more comments on ACS 2004 data were posted on this network. The first is from Ken Cervenka who stated that the concept of continuous surveying appears very sound. I completely agree, we all love to have current data for transportation planning. Unfortunately, the proposed ACS program will not provide us with accurate estimates that we can use. Based on DVRPC analysis, the sampling and nonsampling errors in the ACS data are very large, and the CB simply cannot produce TAZ data comparable to those obtained from the long-form of Census 2000. There are many reasons for this statement, including the ACS sample size is smaller than that of the long-form of the decennial census; it is almost impossible to improve the quality of various data sets to estimate the moving five year average; and the ACS sample does not include group quarters population. As you stated correctly, the ACS approach requires not only sufficient sample sizes, but good annual weighting factors at the sub-county level. Re-weighting ACS samples by sub-county estimated population will not improve the quality of ACS data greatly. The CB would argue correctly that sub-county population estimates have larger errors than those at he county level. Many of the variables used by the CB to estimate demographic data, such as immigration and vital statistics, are only available at the county level. In addition, bias in selecting the ACS samples, large non-response rates from certain population groups, and lack of large marketing programs to promote the ACS and enhance the quality of data collection and processing, are additional reasons for the large errors in the ACS data. Sam Granato wrote that there is no need to even think about reviving the long-form because Congress has not forgotten yet the outcry from bureaucrats and people in 2000. Apparently, he is not impressed by the quality of either the long-form or the ACS data, and wants to develop his models based on SF1 data and secondary source information. I suggested bringing back the long-form because of many reasons, including the following: 1. There are large errors in the ACS data and the data cannot be corrected easily or used for modeling and traffic analysis. There are no solid basis for correcting the ACS estimates, such as census population counts; 2. The errors in the long-form data are much smaller than those in the ACS data. The errors can be corrected by data users based on SF1, SF3, and other census data. For example, the DVRPC region contains 9 counties in Pennsylvania and New Jersey, 355 municipalities and 1912 traffic analysis zones. The evaluation of CTPP data indicated that the population of 9 municipalities was erroneous, the employment in 15 percent of the zones was not coded correctly, and only 1 zone was not located correctly. The data in Tables 3-03 through 3-07 in Part 3 of CTPP cannot be used, not because of major errors in the long-form data, but because of an arbitory decision by the CBs Disclosure Review Board regarding rounding and disclosure threshold; 3. The cost of the long-form is lower than that of ACS. In the late 1990s, the CB stated that the cost of ACS is much lower than that of the long-form, but in May 2005, it stated in Irvine, CA that the cost of ACS is equal to the cost of the long-form data. Since the ACS sample size is about 70 percent of the long-form sample size, the ACS cost is actually about 30 percent higher; 4. According to the CB, Census 2000 was very successful because Congress was interested in accurate population counts, which required the development of several expensive marketing and technical programs to enhance methods of data collection and processing and quality control measures. Most of these programs are not being implemented in the ACS program; 5. Based on DVRPC experience, the errors in data from secondary sources are higher than those in the CTPP. Also, some variables we use in modeling are not even available. For example, the CTPP is the only source for employed persons by place of residence and place of work at the TAZ level. To collect demographic and employment data at the TAZ level will cost millions of dollars. The long-form data are free. Because of this, DVRPC has decided to depend on census data for regional and transportation planning studies. Although not perfect, the responses to the long-form are the best source available to us for various transportation studies; and 6. Many planners remember that the CB wanted to delete the long-form from Census 2000, but could not do it because of the outcry of some bureaucrats from FHWA, FTA, OMB, state DOTS, and MPOs. With the ACS Program, Congress is now getting the outcry from the people annually, and some members prefer to hear all of the outcrying in the decennial census year. I think that the CB is completely capable of producing quality data in Census 2010, including the data we need for the transportation planning. After all, the CB has been doing it for 40 years. In order to produce quality data in Census 2010, the CB should improve its nonsampling procedures, call back, or reinterview some of those who do not respond to the long-form questions, develop an accurate geocoding of the place of work addresses, continue its successful public relations and marketing programs, change rounding rules, and eliminate the disclosure threshold.

20 years, 5 months

Availability of CTPP CDs and DVDs on Transtat

by Chuck Purvis

Just a note to let Census Bureau & USDOT folks know that the CTPP Part 3 DVD for California was shipped 9/12/05 and was received in our offices on 9/19/05. Question: When will the CTPP CDs and/or DVDs be available from BTS? Will this be on the BTS Transtat site, or elsewhere? http://www.transtats.bts.gov/ Thanks in advance, Chuck P. ************************************************************** 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/ **************************************************************

20 years, 5 months

2004 ACS

by Sam Granato

No point in even thinking about reviving the long form. I'm sure our Congress folk haven't forgotten yet the outcry they got not from us bureaucrats but from "real people" back in 2000. I don't even recall long form data being that great either - even by 1990 the non-response and obvious mis-response were getting pretty high. I'm at the point now where due to this plus the timeliness of CTPP I'm developing metro travel models virtually all from SF1 and "secondary source" information, with long-form data only for control totals or relative adjustments to the totals from other sources. I'd rather see the Census Bureau concentrate first on getting the short-form numbers and the geography right, that'll be plenty enough of a challenge in 2010 and beyond. Sam Granato Ohio DOT, Office of Technical Services 1980 W. Broad Street, Columbus, OH 43223 Phone: 614-644-6796, Fax: 614-752-8646 "I think there is some methodology in my travels." - George W. Bush Of all the things that you outlined for alternatives to replace the ACS, I would say bring back the long-form. I know it is not easy to reverse the decision that was made by the CB two years ago. Although not perfect, the responses to the long-form will be more reliable because it will be conducted with the decennial census, which is respected by almost everyone in the country. I think that FHWA should take the lead in promoting this effort and tell the country that the ACS data are not acceptable for the transportation community since the margin of error is very large. I really don’t know the effective channels of communication to have the long-form back in Census 2010. But I think the ACS issues should be brought to the attention of decision makers within AASHTO, APTA, NARC, TRB, Public Data Users, 2010 Census Advisory Committee, AMPO, 2010 Census Advisory Committee, AMPO, House Subcommittee on the Census, and other organizations. Of course political pressure is always needed. The other options you outlined are not really alternatives to the long-form. Improvements to the ACS county program will help a little but won’t solve the problem. Large surveys similar to the surveys conducted in the 1950's and 1960's are out of the question.

20 years, 5 months

RE: [CTPP] 2004 ACS Data Release

by Ken Cervenka

Hello, As is most likely the case for many other lurkers on the CTPP listserv, I have been reading the recent slew of ACS-related emails with great interest. Exactly what to make of all this--I am still not sure. Conceptually speaking, the ACS concept of "continuous surveying" with permanent/experienced Census Bureau staff, as opposed to once-every-10-years surveying with a large group of temp employees, appears very sound. Even the idea of a "moving five-year average" to get a finer level of area-to-area detail sounds both workable, better, and timely than what we could ever get in the past. Once a lot of statistical analysis has been performed, I would expect our leading university researchers to come up with useful ways to turn various sets of "moving five year averages" into reasonable specific-year datasets that would be adequate for use with our future local household survey expansions, population synthesis procedures for travel microsimulations, and basic "so this is what is happening in our region" data summaries. Unfortunately, the ACS approach requires not only sufficient sample sizes for any given year, but a good annual weighting (expansion) process to deal with sub-county geographic and other biases. If I am understanding things correctly, the only weighting to be applied will be at the County level? Maybe I am missing something, for I don't see how this will result in anything but much too much year-by-year variation in household characteristics--it puts way too much pressure on an underlying implicit assumption that the number of households in a County that wind up in each year's dataset are truly representative households for not only the County, but any future sub-County disaggregations that are prepared. I suspect this is why some folks have been noting some big year-by-year changes in important household statistics (autos per household, average household size, etc.) that may not be reflecting real-world annual changes. I can certainly understand some of the difficulties that would be encountered, but it seems like some modified approach is needed to re-weight the yearly Household ACS samples within Counties by something other than a single county-specific factor. If this was a Year 2000 small-sample local household travel survey we would be able to correct for the most significant within-County response biases by using the Year 2000 Census data as the real-world "truth" for coming up with household-specific weighting factors. But it's not clear what source could be used for a more realistic/useful weighting of annually-collected ACS records. It's not the current ACS sample size that bothers me (although I will be distressed if the sample size should ever get reduced from current levels), but rather the ACS weighting/expansion procedures. Or...maybe I am missing some important point about the ACS weightings, for which I will actually be grateful to be publicly corrected. Just call me, "perplexed in Dallas". Ken Cervenka NCTCOG (Dallas-Fort Worth MPO) -----Original Message----- From: ctpp-news-bounces(a)chrispy.net [mailto:ctpp-news-bounces@chrispy.net]On Behalf Of Richard Lin Sent: Tuesday, September 20, 2005 8:31 PM To: ctpp-news(a)chrispy.net; tzakaria(a)dvrpc.org; Elaine.Murakami(a)fhwa.dot.gov; TMarchwinski(a)njtransit.com Subject: RE: [CTPP] 2004 ACS Data Release Dear T, I completely agree with your comments on the serious limitations of ACS data. Comparing to your desire to apply the ACS data for transportation, I am very disappointed about the quality and limitations of ACS to serve as reference data for evaluating our annual county and municipal estimates of population and households. However, there are many other data users out there hoping to get timely demographic characteristics for making decisions involving either to spend money or to get money. Less accurate statistics information is still better than no information for decision making. Sample statistics from the decennial census long form (from 1/6 of households or 17 million household samples in Census 2000) indeed are very much better and reliable (accurate) than that from the 838,000 samples from the 2004 ACS survey in a single year. Without the 2004 ACS data, we can only depend on the Census 2000 sample statistics. Do you like that? That is your choice. If so, just don't bother about the ACS survey data for transportation applications. I am still hope to find something worthwhile from the annual ACS survey data to check on the annual estimates of population and households. It is still better than the March Supplement CPS (Current Population Survey) data which only contain about 800 (household) samples for Colorado. As of 7-1-2004 Colorado has more than 2,026,000 households. Comparing to CPS, I appreciate very much to have ACS. How about canceling the ACS program and campaigning to re-install Long Form for Census 2010? You all know that if the Senates do not fund or under fund the ACS test programs for year 2006 and the years after, it is highly likely that the Census Bureau has to abandon ACS program and request funding to work on Long Form for 2010 Census. How many of you would like to see that happen? >>> <TMarchwinski(a)njtransit.com> 9/17/2005 12:51 PM >>> Dear Mr. Lin- I disagree with you about census long form vs. ACS. I cannot use the ACS for any transportation planning analysis except maybe to see where general trends are going. Even there, looking at NJ data by county, there are some weird changes in mode data even from year to year. I use the 2000 Census data almost every week, and the ACS, unless it can get down to a smaller geography, does not do much good. Unless you are doing some high level comparisons about average travel time or average mode split etc., it cannot be used for what most transportation planners need, such as trip distribution, mode split, auto occupancy, vehicle ownership etc. If there is no long form, then we will have to take what we can from the ACS and combine it with other data, surveys etc. -----Original Message----- From: ctpp-news-bounces(a)chrispy.net [mailto:ctpp-news-bounces@chrispy.net] On Behalf Of Richard Lin Sent: Friday, September 16, 2005 7:48 PM To: ctpp-news(a)chrispy.net; tzakaria(a)dvrpc.org; Elaine.Murakami(a)fhwa.dot.gov Subject: RE: [CTPP] 2004 ACS Data Release Dear All, We all realize the limitations and quality of the ACS data. Also, we all are seeking better resolutions. First of all, we hope the Census Bureau gets enough funding to carrying out ACS operations and to improving the quality of data by accumulating greater samples. Hope by Census 2010, the quality of the ACS data is equal to or even better than that of the traditional long form. Without annual ACS survey, we will fall back again to the once a 10-year long form data availability. Will you prefer still using the Census 2000 Long Form data in 2005 or do you appreciate the limited 2000-2004 ACS data? Without the annual ACS data, we will go back to the dark again. The good news is that if the Census Bureau gets funding to continue ACS survey through Census 2010 then we should have much more reliable and larger sample ACS data for better quality time series. With the sampling error variation, we should be more cautious about time series fluctuations and verify the true changes in numbers such as the Jew Jersey's Mercer County having lesser workers riding bikes or walk to work (5,450 or 3.5 in Census 2000 comparing to 2,924 or 1.9 in ACS 2004). We should also be cautious when we compare apple to orange. We may check the data at state (NJ) level by comparing the state's Census 2000 numbers and ACS 2000 numbers to establish a ratio factor for county adjustment for time series comparison. >>> "Murakami, Elaine" <Elaine.Murakami(a)fhwa.dot.gov> 9/14/2005 1:39:12 PM >>> Dear Zak, Thank you for providing your opinion on the disutility of the ACS 2004 data for your applications, and I am glad that others are examining data for their area and are sharing their findings with the listserv. My earlier email was sent to CAUTION people who might try to compare 2000 decennial data to ACS 2004 data. As I said in my earlier email, it is probably better to compare ACS results to ACS results, than to compare ACS results to decennial census results, however, results from ACS from 2000 are very limited. The geographic coverage of County level data from the ACS in 2000 is sparse, which makes comparisons for ACS between 2000 and 2004 possible only in some areas. The ACS did not go into "full implementation" until 2005, and it will require multiple years of data collection before data for small areas will be reliable because of the small samples collected each month and averaged over time. As Tom Marchwinski pointed out, averaging over multiple years creates other problems. In 2005, the CB begin differential non-response follow-up, so that in areas (tracts) with low mail-back responses, there is a greater rate (1:2 and 2:5 instead of 1:3) made to follow-up non-respondents from the mail-back and CATI portion of the ACS. Not surprisingly, the areas with low mail-back responses are more likely to be low income, and higher shares of African American and Hispanic populations. My guess is that this will cause a shift in numbers between 2004 and 2005, and could impact variables such as carpooling and transit use and number of vehicles in households. The Census Bureau recommends that the ACS should be used to describe characteristics, and not to use it for COUNTS. When I examine the Mercer County NJ data comparing Census 2000 (workers in households) to ACS 2004 (workers in hhlds), I find that about the only thing to say is that "driving alone" appears to increase from 77 to 78%, and "carpooling" to decrease from 11 to 10%, "rail" also appears to increase from 4 to nearly 6%. (Worked at Home is not included in column in the table below). HOWEVER, this is not taking into account the effects of the different survey methods, where, generally speaking, the decennial census has a greater share reporting "carpooling," which is why a BRIDGE from decennial 2000 data is so important. Thus, it is probably incorrect to say that carpooling is declining. Mercer County, NJ Workers in Hhlds Census 2000 ACS 2004 Number Pct Number Pct Total 153,665 153,041 Drove alone 118,390 77.0 119,597 78.1 2-person CP 13,105 8.5 12,026 7.9 3+ person CP 4,580 3.0 2,722 1.8 Bus/trolley bus 4,585 3.0 4,390 2.9 Streetcar/trolleycar+ 195 0.1 1,168 0.8 Railroad or ferry 6,105 4.0 8,795 5.7 Bike or Walk* 5,450 3.5 2,924 1.9 Taxi/motorcycle/other 1,255 0.8 1,419 0.9 * 2000 is walk + bike, 2004 is walk only The county estimates program which is used to weight the ACS data is drawing considerable fire, as evidenced by the post by Jeffrey P. Levin from the City of Oakland. Things for State DOTs and MPOs to consider if you feel that the ACS will not provide you with quality data: 1. Can your organization leverage enough political resources to bring back a Census "long form" ? 2. Would improvements to the county estimates program make you feel more comfortable with the ACS results? 3. Should your organization consider conducting a very large sample survey, similar to the surveys conducted in the 1950's and 1960's where sample sizes of 3 - 5 % of all households were asked to completed a travel diary? One of the goals of these surveys was to produce an O/D matrix for a limited number of zones. An area with 1 million population might have 400,000 households, therefore a 4% sample would be 16,000 households. Let's estimate the cost of a household survey at a conservative $150 per complete, resulting in a estimate of $2.4 million. Keep in mind that the response rates to recent regional household travel surveys have been between 25-30%, which is much lower than the ACS, thus, risking much higher sample bias. Once you get the results, you will need to determine a method to weight your results for regional totals. 4. Should your organization implement a survey on group quarters population, or do you believe that the ACS will include group quarters in 2006, as planned. 5. Should you find an alternative data source for home-to-work flows. Sorry for the long post, and hope that my table comes over without distortion. Elaine FHWA Office of Planning

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