San Francisco successfully challenged the Census Population Estimates, eliminating about half the discrepancy between Census estimate and DOF. See http://www.sfgov.org/site/mayor_index.asp?id=94792 _________________________________ 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 510/238-6188 FAX: 510/238-3691 http://www.oaklandnet.com/government/hcd This email may contain material that is confidential, privileged and/or intended for the sole use of the intended recipient. Any review, reliance or distribution by others or forwarding without express permission is strictly prohibited. If you are not the intended recipient, please contact the sender and delete all copies ________________________________ From: wendell cox [mailto:demographia@gmail.com] Sent: Thursday, June 25, 2009 2:54 PM To: ctpp-news(a)chrispy.net Cc: Levin, Jeffrey Subject: Re: [CTPP] ACS 2005-2007 Population Estimates Do not know the issue you are raising, however, Calif Dept of Finance estimates are high on municipal populations of SF and LA... by a large margin... this is in comparison to the annual Census Bureau estimates (which may or may not be related to ACS). On Thu, Jun 25, 2009 at 9:28 PM, Shimon Israel <SIsrael(a)mtc.ca.gov> wrote: For ACS 2005-2007 population and housing occupancy/vacancy estimates, are people finding discrepancies between ACS and other data sources, particularly in sub-county geographies? ACS estimates are controlled at the county level and, like the ACS 1-year data, ACS 2005-2007 population estimates are showing disagreement with other data sources. For example, the Oakland 3-year ACS estimate shows the population at 372,000, when CA Dept. of Finance estimates are over 400,000. This runs counter to the on-the-ground anecdotal experience - ACS shows a loss of 30,000 people during a period that showed an increase of 10,000 housing units. Will the decennial census correct this? My understanding is that Census 2010 numbers will be used to control 2010 ACS characteristic data. There will need to be some adjustment, however, given that the decennial census benchmarks population at April 1, and ACS uses a July 1 population number. It's also my understanding that population estimates for 2001-2009 will be updated, though retroactive adjustments for ACS characteristics will not be done. Does anyone else know something different about this? Other thoughts about this? Thanks, Shimon --------------------------------------------------------------- Shimon Israel Associate Transportation Planner/Analyst Metropolitan Transportation Commission 101 Eighth Street Oakland, CA 94607-4700 (510) 817-5839 (office) (510) 817-5848 (fax) --------------------------------------------------------------- _______________________________________________ ctpp-news mailing list ctpp-news(a)chrispy.net http://www.chrispy.net/mailman/listinfo/ctpp-news -- -- Wendell Cox Demographia | Wendell Cox Consultancy - St. Louis Missouri-Illinois metropolitan region Visiting Professor, Conservatoire National des Arts et Metiers, Paris France..33.6.16.63.58.76 USA..1.618 632 8507 www.demographia.com | www.publicpurpose.com | www.rentalcartours.net Books & Publications WAR ON THE DREAM: How Anti-Sprawl Policy Threatens the Quality of Life http://www.demographia.com/wod1.pdf 5th ANNUAL DEMOGRAPHIA INTERNATIONAL HOUSING AFFORDABILITY SURVEY (http://www.demographia.com/dhi.pdf) THE WAL-MART REVOLUTION: How Big-Box Stores Benefit Consumers, Workers, and the Economy By Richard Vedder & Wendell Cox

ACS did not include group quarters in 2005, but did add them in 2006 and 2007. The 3-year period estimates for 2005-07 include them too (adjusting the weighting to account for their absence in the 2005 data). I can't speak for the methodology used by the California Dept. of Finance, but if it is similar to that used by its Washington State counterpart, the administrative data it uses to estimate current population will be different from that used by Census, and can account for a difference in the outcome. (Remember that both agencies are making estimates based on indirect information). Calif Dept of Finance may be using employment records (employees covered by unemployment insurance, which excludes the self-employed), school enrollments, motor vehicle registrations, births, deaths, etc.; while Census has access to births, deaths, employment records, and Social Security records. Typically, the figures from Census do not align with those from the Washington Office of Financial Management, though they are usually in the ballpark. All such agencies benchmark their annual population estimates to the decennial census once those figures come out. Typically they will revise their intercensal estimates back to the previous census, but maybe only for the county totals. Census also will do this, but only for the county totals, not for the ACS figures. You could apply the ACS percentages (e.g., percent age 15-64 in the workforce) to the Calif Dept of Finance totals if you felt those were more reliable totals. ACS is intended to be a source of data on characteristics, not necessarily on total numbers - that's the job of the decennial census, and of intercensal and postcensal totals. Pete Swensson, Senior Planner Thurston Regional Planning Council 2424 Heritage Ct. SW Olympia, WA 98502 (360) 741-2530 (direct line) (360) 956-7575 (main desk) (360) 956-7815 (fax) swenssp(a)trpc.org This e-mail and any attachments are for the use of the addressed individual. If you have received this e-mail in error, please notify our systems manager. TRPC has taken responsible precautions to ensure no viruses are present in this e-mail, however we do not accept responsibility for loss or damage arising from the use of this e-mail or attachments. From: ctpp-news-bounces(a)chrispy.net [mailto:ctpp-news-bounces@chrispy.net] On Behalf Of Mike Harmon Sent: Thursday, June 25, 2009 3:40 PM To: ctpp-news(a)chrispy.net Subject: RE: [CTPP] ACS 2005-2007 Population Estimates You should remember that the ACS estimates include the household population only, whereas the DOF numbers include people in group quarters, which makes the State numbers higher. ________________________________ From: ctpp-news-bounces(a)chrispy.net [mailto:ctpp-news-bounces@chrispy.net] On Behalf Of wendell cox Sent: Thursday, June 25, 2009 2:54 PM To: ctpp-news(a)chrispy.net Cc: JPLevin(a)oaklandnet.com Subject: Re: [CTPP] ACS 2005-2007 Population Estimates Do not know the issue you are raising, however, Calif Dept of Finance estimates are high on municipal populations of SF and LA... by a large margin... this is in comparison to the annual Census Bureau estimates (which may or may not be related to ACS). On Thu, Jun 25, 2009 at 9:28 PM, Shimon Israel <SIsrael(a)mtc.ca.gov> wrote: For ACS 2005-2007 population and housing occupancy/vacancy estimates, are people finding discrepancies between ACS and other data sources, particularly in sub-county geographies? ACS estimates are controlled at the county level and, like the ACS 1-year data, ACS 2005-2007 population estimates are showing disagreement with other data sources. For example, the Oakland 3-year ACS estimate shows the population at 372,000, when CA Dept. of Finance estimates are over 400,000. This runs counter to the on-the-ground anecdotal experience - ACS shows a loss of 30,000 people during a period that showed an increase of 10,000 housing units. Will the decennial census correct this? My understanding is that Census 2010 numbers will be used to control 2010 ACS characteristic data. There will need to be some adjustment, however, given that the decennial census benchmarks population at April 1, and ACS uses a July 1 population number. It's also my understanding that population estimates for 2001-2009 will be updated, though retroactive adjustments for ACS characteristics will not be done. Does anyone else know something different about this? Other thoughts about this? Thanks, Shimon --------------------------------------------------------------- Shimon Israel Associate Transportation Planner/Analyst Metropolitan Transportation Commission 101 Eighth Street Oakland, CA 94607-4700 (510) 817-5839 (office) (510) 817-5848 (fax) --------------------------------------------------------------- _______________________________________________ ctpp-news mailing list ctpp-news(a)chrispy.net http://www.chrispy.net/mailman/listinfo/ctpp-news -- -- Wendell Cox Demographia | Wendell Cox Consultancy - St. Louis Missouri-Illinois metropolitan region Visiting Professor, Conservatoire National des Arts et Metiers, Paris France..33.6.16.63.58.76 USA..1.618 632 8507 www.demographia.com | www.publicpurpose.com | www.rentalcartours.net Books & Publications WAR ON THE DREAM: How Anti-Sprawl Policy Threatens the Quality of Life http://www.demographia.com/wod1.pdf 5th ANNUAL DEMOGRAPHIA INTERNATIONAL HOUSING AFFORDABILITY SURVEY (http://www.demographia.com/dhi.pdf) THE WAL-MART REVOLUTION: How Big-Box Stores Benefit Consumers, Workers, and the Economy By Richard Vedder & Wendell Cox

The first thing to understand is that while the ACS county estimates are controlled to the census population estimates, the sub-county estimates are not. The numbers that appear for cities are just what the weighted data show. For Detroit, they are always too low. There is always a lag in terms of getting new housing units into the sampling frame (the Master Address File, or MAF), while there is loss when a sample address turns out to be demolished or vacant. I don't know if that the 2010 ACS data are going to be weighted to the census results. I don't think they've thought about that yet. If they are, there won't be any problem updating from April to July. We do not usually see redone intercensal estimates after the census, and I'm sure that there won't be any adjustment of ACS results. Bottom line: be very careful in using whole numbers from the ACS, and when you do, always round them to '00s (hundreds) so that people will understand that they are estimates and not counts. ACS is really best for the data that are expressed in percentage terms. Patty Becker At 05:28 PM 6/25/2009, you wrote: ------------------------------------------------------------------------------------------------- Patricia C. (Patty) Becker 248/354-6520 APB Associates/SEMCC FAX 248/354-6645 28300 Franklin Road Home 248/355-2428 Southfield, MI 48034 pbecker(a)umich.edu

I appreciate everyone's responses. I'm also curious if anyone knows what 3- and 5-year ACS data sets will benefit from Census 2010 population counts. Will the 2008-2010 3-year and 2006-2010 5-year (both released in fall 2011) be the first small area data sets to use the 2010 decennial census to develop period estimates? --------------------------------------------------------------- Shimon Israel Associate Transportation Planner/Analyst Metropolitan Transportation Commission 101 Eighth Street Oakland, CA 94607-4700 (510) 817-5839 (office) (510) 817-5848 (fax) --------------------------------------------------------------- Shimon: I just wanted to add my comments about ACS and population figures, based on my own experience in the Little Rock region and my agency, Metroplan (the MPO for this region). 1. I have found similar disagreement between my population/housing estimates and the ACS. The census estimates upon which ACS is based have tended to under-count population in past decades, so it's not unreasonable to assume they're doing the same now. 2. Due to a quirk in state law, Arkansas has a number of mid-decade special censuses in fast-growing cities. In 2005-2007 we went through a cycle of these in which, as usual, Metroplan's population estimates came very close to the special census figures, while the census estimates were often low. 3. A firm in our region, the Gadberry Group, has developed its own system of estimating population based on consumer data. While this runs into that scary "death of privacy" issue, these guys use the things the corporate world knows about us to estimate population, household income, ethnicity etc. to sell as marketing information to large retailers and other firms. Anyway, the Gadberry Group's population estimates for our region have come in considerably higher than our own estimates, and hence that much higher than the generally low census estimates. I don't know what this means. I think Gadberry estimates are a bit too high, but this may be further verification that census estimates run low. 4. While they would not release specific information, Gadberry endorsed my view, supported by recent ACS results, that household size has risen and occupancy has dropped recently in local communities in response to the housing and economic crisis. While there has been a lot of criticism of ACS, my intuition is that it's on the right track and the qualitative information it provides fits with hints from other data sources. That said, I think we all need to be looking at ACS results with circumspection; it's only been around a few years. There are always surprises when the census figures finally come out. I'm sure Census 2010 will be no exception. Jonathan Lupton Research Planner Metroplan 501-372-3300 _______________________________________________ ctpp-news mailing list ctpp-news(a)chrispy.net http://www.chrispy.net/mailman/listinfo/ctpp-news