RE: [CTPP] [ctpp-news] Demographic Analysis for BlockGroups -Decennial Census vs. ACS 5 Year Estimates

Hi Megan -- thanks for note re: B17005 not available at BG level. I found Appendix E that shows which tables do or do not have a BG tabulation. When we reviewed this list early on, we focused on the "B08xxx" tables for journey to work. http://www2.census.gov/acs2009_5yr/summaryfile/ACS_2005-2009_SF_Tech_Doc .pdf The 5-year CTPP (2006-2010 ACS records) will include a table of sex by employment status. The current table number (in the 3-year CTPP) is 11205. The smallest geographic unit depends on the selection by the MPO or State DOT, with the default being census tract, and many MPOs currently delineating TAZs (often similar in size to a block group). There are a few tables in the CTPP using "poverty", but most of them are tables with households as the universe (not persons). However, the 5-year CTPP is not expected to be done until early 2013. Elaine -----Original Message----- From: ctpp-news-bounces(a)chrispy.net [mailto:ctpp-news-bounces@chrispy.net] On Behalf Of Cogburn, Megan S Sent: Thursday, April 07, 2011 10:52 AM To: ctpp-news(a)chrispy.net Subject: RE: [CTPP] [ctpp-news] Demographic Analysis for BlockGroups -Decennial Census vs. ACS 5 Year Estimates Everyone has raised valid points in that ACS 5 Year Estimates are only samples and have a high margin of error. However, with ACS replacing the long form, there seems to be no other option for block group analyses. Am I right here? Elaine - B17005 is not available at the block group level, at least from what I've found. I used the Summary File Retrieval Tool which is an Excel macro and was unable to obtain block group data for B17005 for any North Carolina county. This is of particular concern, which raised my question of where to get this data (along with a few other variables) since it appears NOT to be available at the block group level. -----Original Message----- From: Elaine.Murakami(a)dot.gov [mailto:Elaine.Murakami@dot.gov] Sent: Thursday, April 07, 2011 12:58 PM To: ctpp-news(a)chrispy.net Subject: RE: [CTPP] [ctpp-news] Demographic Analysis for Block Groups -Decennial Census vs. ACS 5 Year Estimates 1. Multi-year accumulations instead of "point-in-time" data collection. I am guessing that Megan is concerned that the ACS requires multiple years (actually 60 months of survey data) before tabulation for small geography. Yes, with the implementation of the ACS, the Census Bureau made a big trade off for currency of large geographic reporting (annual for areas with 65,000 population or more), and a long period of collection for small area (tracts and block groups). When so many things are volatile, like gasoline prices, housing prices, and unemployment, it makes the 5-year accumulation problematic. For example, when gasoline prices rose to over $4/gallon in 2008, travel mode to work did change somewhat, with more people using transit. http://www.eia.doe.gov/oil_gas/petroleum/data_publications/wrgp/mogas_ho me_page.html (I know, because my bus ride became very crowded! But now that prices are heading that high again, maybe because it has been more gradual and not a spike, I don't see increased demand on my bus). I have heard some people say that they would prefer to go back to a point-in-time estimate, but I don't think that it is realistic to think that the decennial "long form" will come back. 2. B17005 : Poverty by Sex by Employment Status IS in the ACS 5-year data, Summary File format only. 3. Cautions with using LEHD OTM. As with every dataset, the more you know about it, the better off you are. LEHD OTM includes workers who are covered by unemployment insurance, and excludes self-employed (approx 10% of workers). Currently, federal workers including military are not included, and also state workers and school district employees have often found to be mis-located, particularly to state capitols (for state workers), and school district headquarters for school employees. Also, it is important to understand that the link between home and work location is the result of a data synthesis process to assign workers to a home location using a distribution algorithm based on records from Minnesota, because in Minnesota, employers are required to report the actual work location. In an LEHD OTM webinar held last year, Robert McHaney discussed a parking study in Austin. http://lehd.did.census.gov/led/library/webinars.html They looked at blocks that were outliers for employment densities, and found a regional post office and a school district headquarters. After removing these 2 blocks the total employment in the study area was reduced from 60,000 to 30,000. 4. I am interested in using alternative approaches to capture origin-destination patterns, particularly things like cell phone tracking, RFID tags, stand-alone GPS (not personal cell phone), BlueTooth tracking, etc. I co-chair a New Technology subcommittee of the TRB Travel Survey Methods committee (ABJ40), where we often discuss these topics. http://www.travelsurveymethods.org/Tech.asp Elaine -----Original Message----- From: ctpp-news-bounces(a)chrispy.net [mailto:ctpp-news-bounces@chrispy.net] On Behalf Of Cogburn, Megan S Sent: Wednesday, April 06, 2011 12:58 PM To: ctpp-news(a)chrispy.net Subject: [CTPP] [ctpp-news] Demographic Analysis for Block Groups -Decennial Census vs. ACS 5 Year Estimates My name is Megan Cogburn and I am a Community Planner with the North Carolina Department of Transportation. My group is a part of the Project Development and Environmental Analysis branch and we are responsible for completing all of the NEPA documentation for bridge and highway projects statewide. Specifically, we prepare technical reports assessing potential project impacts on the human environment from the local/urban planning perspective. We currently use decennial Census data for our demographic analyses, however we are thinking of switching to use American Community Survey data to make our reports more current and since the American Community Survey has now replaced the traditional decennial Census long-form. However, it has come to our attention that ACS data is only available at the block group level for 5 Year Estimates (and not annually). Moreover, certain tables that were available for the 2000 Census are not available in the ACS 5 Year Estimates (such as household type by relationship, sex by employment status, and poverty status). Another glaring issue is that ACS 5 Year Estimates were just released in 2010, so there is no previous data to make historical comparisons. So, my question for the listserv is how other organizations are moving forward given the discrepancies between the two datasets. My group is trying to figure out where to get missing data, how to make historical comparisons, and also the best way to retrieve ACS 5-Year Estimates. A huge drawback for us is that we use block group data for multiple variables and this is only available for the 5 year estimates. In order to retrieve summary file data for block groups you have to use an Excel macro retrieval file that takes an extremely long time, download a massive file from their FTP site, or use the not so user friendly Data Ferret platform. Please advise! Megan Cogburn, MCRP Community Planner | Human Environment Unit NCDOT Project Development & Environmental Analysis e: mscogburn(a)ncdot.gov p: (919) 707-6062 f: (919) 212-5785 Email correspondence to and from this sender is subject to the N.C. Public Records Law and may be disclosed to third parties. _______________________________________________ ctpp-news mailing list ctpp-news(a)chrispy.net http://www.chrispy.net/mailman/listinfo/ctpp-news Email correspondence to and from this sender is subject to the N.C. Public Records Law and may be disclosed to third parties. _______________________________________________ ctpp-news mailing list ctpp-news(a)chrispy.net http://www.chrispy.net/mailman/listinfo/ctpp-news