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[CTPP] ACS Proposal: Please comment by Oct 31st

by Chuck Purvis

I'm forwarding this recent message from the State Data Center Listserv. Chuck Purvis, MTC ********************************************************************************************************************************* >>> "Gage, Linda" <Linda.Gage(a)DOF.CA.GOV> 10/18/06 1:57 PM >>> The American Community Survey Office has posted a draft document describing a first-ever ACS summary file. All comments on the proposed approach described in this document must be sent via email no later than October 31. You can access the document at the following website: http://www.census.gov/acs/www/Products/users_guide/New_ACS_Summary_File_Spe… or, open the document at the bottom of this page: http://www.census.gov/acs/www/Products/users_guide/ Send any comments you have to Nick Spanos: nicholas.m.spanos(a)census.gov

18 years, 10 months

[CTPP] Nation's Population to Reach 300 Million on October 17th

by Ed Christopher

The "crystal ball in Times Square" is starting to drop! ---------------------------------------Nationan's Population to Reach 300 Million on Oct. 17 The U.S. Census Bureau today reported that the nation's population will reach the historic milestone of 300 million on Oct. 17 at about 7:46 a.m. (EDT). This comes almost 39 years after the 200 million mark was reached on Nov. 20, 1967. The estimate is based on the expectation that the United States will register one birth every seven seconds and one death every 13 seconds between now and Oct. 17, while net international migration is expected to add one person every 31 seconds. The result is an increase in the total population of one person every 11 seconds. http://www.census.gov/Press-Release/www/releases/archives/facts_for_feature… -- Ed Christopher 708-283-3534 (V) 708-574-8131 (cell) FHWA RC-TST-PLN 19900 Governors Dr Olympia Fields, IL 60461

18 years, 10 months

RE: [CTPP] CTPP Discussion Issues

by Zakaria

Hi Ken: I read your excellent analysis of Census 2000 Part III tract-level, county-level and state-level data sets. Your findings in the detailed spreadsheet for 12 counties in Texas are not unique to Texas. According to my evaluation of CTPP 2000 data for the Delaware Valley Region, the errors and completeness of census data stem mainly from rounding and disclosure threshold rules. The 2000 rounding and disclosure threshold rules resulted in 3 and 62 percent loss in the worker flow at the TAZ level, respectively. As you know, Table 3-06, which shows TAZ-to-TAZ worker flow by means of transportation to work became totally useless due to suppressed flow of workers. It is simply not possible to have synthesized Part III dataset at the TAZ level. We tried to develop a rational and convenient method to do this but we could not and thus were unable to use TAZ-to-TAZ data by means of transportation to work. Relaxation of the disclosure rules would not solve the problem. If the 2000 disclosure threshold were decreased from 3 unweighted workers to 1, the damage to the TAZ-to-TAZ worker flow would be significant still and the data would be useless. Based on this evaluation, I recommended last year not to use any disclosure threshold in the future. There was no disclosure threshold in the 1990 census and no one complained because of disclosure. Imputation, swapping and data rounding were used in the 1990 census to protect confidentiality and were sufficient to avoid disclosure. The "super TAZ" concept will not work in the northeast states, as well as Michigan, Wisconsin and Minnesota because these states have many small minor civil divisions, which consist of only one TAZ. Such small municipalities are interested in their own data. Also, data from "super TAZs" will not be useful for planning small transportation projects such as subway stations, highway interchanges, park and ride lots and local bus routes. Finally, I should state that the margin of error in the ACS tabulation will be larger than that found in Census 2000. The CB is saying now that the 2005 ACS will provide data for areas of 65,000 population and larger because the sample size was increased from that of 2004. Yet the 2005 ACS sample was not large enough to produce a table for all means of transportation to work and a table for workers by place of work and by industrial sector. This information was suppressed completely for Gloucester County, NJ (277,000 population), not 65,000 as promised by the CB. I know that Ed Christopher, Elaine Murakami, Jonette Kreideweis, Dave Clawson, Alan Pisarski, Nanda Srinivansan and others are aware of these CTPP issues. Hopefully, they will be able to resolve these problems and produce accurate CTPP data in the future. Thabet Zakaria Deputy Director, Technical Services Delaware Valley Regional Planning Commission Philadelphia, PA 19106 Phone: 215-238-2885 Email: tzakaria(a)dvrpc.org Fax: 215-592-9125 -----Original Message----- From: ctpp-news-bounces(a)chrispy.net [mailto:ctpp-news-bounces(a)chrispy.net] On Behalf Of Ken Cervenka Sent: Tuesday, October 03, 2006 2:17 PM To: ctpp-news maillist Subject: RE: [CTPP] CTPP Discussion Issues Ed, Thanks for the additional info. The issues raised in the draft email I was working on relate to what you just said: 1) the idea of larger TAZs to limit disclosure problems; and 2) the idea of data synthesis to still get very small-area data. So my apologies for redundancy in addressing the same thing below, but in different words. ********************************************************************* Ed said at the end of his email to post questions/comments to the listserv, so... I do indeed hope AASHTO will approve the new CTPP Pooled Fund initiative. In spite of the difficulties "us MPOs" and other organizations have with uncertainties on the accuracy of Census products (and the ACS and CTPP 2000 comparisons people have been making are pointing out some important issues), and the impacts of disclosure rules applied to journey-to-work tables, the "long form" questions are nevertheless still important to the transportation planning process. As others before me have said (I recall Alan Pisarski giving a speech or two or three on this topic), the word "data" is not particularly glamorous to people outside the profession (and oftentimes rather boring to those within the profession), but yet represents the foundation to an informed (and democratic) decision-making process. So with those sincere accolades on the underlying importance of CTPP data--and hopes for AASHTO pooled funding--stated, now on to the technical issues. The current disclosure rules have been a major hindrance to "good" small-area transportation planning in which we want more than simply place-of-residence and place-of-work information: now I understand why the Census Bureau must always retain procedures that maintain confidentiality of individuals, but I wonder if there isn't more to be checked and confirmed, just to be sure that the "rules" in place are not being too restrictive. The impacts of the restrictions have been discussed many times before, but can be easily seen by working with the Census 2000 Part III tract-level, county-level, and state-level datasets available from: http://www.transtats.bts.gov (note: when you are at this location, just type in CTPP 2000 Part III in the "search this site" box to get to the appropriate downloading page). The attached spreadsheet shows some statistics for 10 different states, in which I summarized the Tract-to-Tract data in the State, for selected variables. Since not everyone's email is set up to receive attachments, here is the gist of what's shown on the spreadsheet: -- Question T301C1 represents total workers, which for these 10 states is 56,157,132 workers. -- Question T302C1_1 represents all workers residing in households that are definable by their "vehicles available in household" and seven "Means of Transportation" aggregated categories; the 10-state total is 55,643,556 workers, which is equal to 99.1% of the total workers (I presume the very minor loss in workers is due to the "residing in households" definition). -- Question T305C1 represents all workers residing in households that are definable by a household income category; the 10-state total is 65.7% of the total workers. -- Question T306C1 represents all workers residing in households that are definable by one of the 17 "Means of Transportation" detailed categories; the 10-state total is 66.4% of the total workers. Of equal significance are the variations of "completeness" for each of these 10 selected states, e.g., for Question T306C1 there is a range of 56.0% for New York to 79.8% for Oregon. When confronted with these "missing data" issues, I suspect some planners simply factor up the available trip table so it appears to represent the full universe--but even a cursory examination of county-level Part III trip tables versus "Part III tract-level aggregations to county" trip tables will show that the missing data is not equally represented across all categories. For example, consider the 17 "Means of Transportation" data for Dallas County: the tract-level aggregations represent 60% of the reported county-level total for drive alone trips; 80% of the total for walk trips; and 100% of the total for work-at-home trips. So if someone used a simple factoring process across all modes in the tract-level datasets to reach the full universe, the end result is that the actual number of drive alone trips would be significantly under-represented and the number of walk trips and work-at-home trips would be significantly over-represented in the factored tract-to-tract data. [Note: if anyone is interested, I have a detailed spreadsheet that shows these issues for 12 counties in Texas--but it is a rather messy spreadsheet that has not been thoroughly checked, so I don't want to forward to people unless they ask me via private email, and promise not to forward to a listserv]. Since most TAZs (at least as defined by the MPOs) are generally a LOT smaller than Census Tracts, the TAZ-to-TAZ trip tables from the CTPP 2000 effort wind up having even greater amounts of missing data for the income-related and "detailed means of transportation" categories. Which brings up two possibilities for future improvement (assuming there will be Part III datasets in the future at anything other than a County or PUMA level): 1. I wonder if there might be opportunities to someday have two sets of TAZ-to-TAZ files: one dataset would have the same "missing records" limitations we currently see (and agonize about), and the other dataset would be based on a process that uses some of the held-back information to "synthesize" the missing data to develop a fully-complete TAZ-to-TAZ table. Now independent researchers can already use various "Iterative Proportional Fitting" or similar imputation procedures to deal with missing data issues, but I am concerned that their techniques will not be as good as what the Census Bureau staff could do, since the CB staff would have access to more of the underlying raw data that would (or at least could/should) result in a "better" synthesis process. Now I can understand the cost implications and potential confusions of two sets of "official" TAZ-to-TAZ data, but this would give us end-user planners the greatest number of choices for making decisions about future land use and capacity changes. Plus, by making the "missing records" tables available, this would still give agencies an opportunity to conduct (at their own expense) their own imputation process that could then be compared against the CB's synthesized tables. 2. If it is simply not possible to have a synthesized Part III dataset at the TAZ level--and there is not much hope for any significant relaxation of the disclosure rules--then maybe we need to pay great attention to the "Super TAZ" concept, in which each TAZ is carefully defined so that it is "just large enough" to reduce the more serious confidentiality issues, while still being useful for planning. An example would be a typical CBD: this is MUCH smaller than a County or PUMA, but is often composed of many existing TAZs and Census Tracts. So instead of having a CBD represented by 25 TAZs, maybe it could be divided into just four or five TAZs--or even just one TAZ, if that's what it takes to keep the understandable confidentiality issues from over-taking our desires for a more democratic decision-making process that is based on understanding the world we live in. Ken Cervenka North Central Texas COG (Dallas-Fort Worth MPO) Kcervenka(a)nctcog.org ************************************************* -----Original Message----- From: ctpp-news-bounces(a)chrispy.net [mailto:ctpp-news-bounces(a)chrispy.net] On Behalf Of ed christopher Sent: Tuesday, October 03, 2006 12:35 PM Cc: ctpp-news maillist Subject: Re: [CTPP] CTPP Discussion Issues Ken--the short answer is yes; Part 1, part 2 and Part 3 (flow data). With that said there will be some caveats and of course of lots of issues to be discussed, debated, researched and decided upon. In hearing from users and those active on the AASHTO SCOP Data Working Group people have been very clear that they want small area TAZ to TAZ flow data. Under the proposed pooled-fund, that would happen but certain concessions would have to be made to accommodate the Census Bureau's Disclosure Review Board concerns. One very practical notion on the table is to have a larger geography (call it a super TAZ for now) where we would have all our data with no suppression or other disclosure rules. From that we would extend a more traditional data package for the smallest zones (traditional TAZs) that would likely be synthesized. Some spot research is going on in this vein and the proposed pooled-fund calls for more as well as an NCHRP 8-36 proposal that we are hopeful will get funded. For now before we get too far a field I think it is critical to see that the pooled-fund comes to fruition. Ken Cervenka wrote: > Ed (or anybody) > > Could you please confirm that when you talk about TAZ data, you are > referring to not simply Place-of-Residence (Part I) and Place-of-Work > (Part II) summaries at the TAZ level, but the possibility for TAZ-to-TAZ > (Part III) datasets? If there is still hope for future TAZ-to-TAZ (or > super-TAZ to super-TAZ) dataset deliveries, I have lots to say on the > subject, that I am willing to put out on this listserv. > Ken C. > > -----Original Message----- > From: ctpp-news-bounces(a)chrispy.net > [mailto:ctpp-news-bounces(a)chrispy.net] On Behalf Of ed christopher > Sent: Monday, October 02, 2006 10:19 AM > To: ctpp-news maillist > Subject: [CTPP] CTPP Discussion Issues > > During the past few months I have received several questions regarding > the need for small area, Traffic Analysis Zone (TAZ), data from the > American Community Survey (ACS) so I thought I would provide an update. > > GENERAL UPDATE ON CTPP > > There are two groups that are working on census data needs for the > transportation community. > > First there is the long-standing CTPP Working Group that meets monthly > and has been responsible for the content of the 1980, 1990 and 2000 data > packages. Although the precise membership of this working group has > changed over time it has generally been made up of US DOT staff, Census > Bureau (CB) staff, Dave Clawson from AASHTO, and members of > Transportation Research Board (TRB) committees. The work of the CTPP > Working Group tends to focus on the highly technical aspects of the > data. Since 1997, this group has met at least once a month and has been > chaired by Elaine Murakami of FHWA. > > Working in concert with the CTPP Working Group, the AASHTO Standing > Committee on Planning (SCOP) last August (2005) initiated a broader > based Committee called the SCOP Census Work Group. Jonette Kreideweis > of the Minnesota DOT chairs this group. Its main focus has been on > issues that transportation planners need to know to use the ACS and it > has been instrumental in recognizing that a "family" of new data > products will be needed. In June the Work Group proposed a pooled-fund > project that includes data products, research, training, and technical > support. The pooled-fund is currently before SCOP and I hope that it > will be approved by AASHTO in October. The pooled-fund builds upon the > experience gained from the 1990 and 2000 pooled-fund projects and > details on it can be found on the TRB Subcommittee on Census Data > website at http://trbcensus.com/SCOP/ > > TAZ DEFINITION for ACS > > 1. Will MPOs and State DOTs be asked to submit new TAZs? > > Assuming that a new CTPP pooled-fund is approved by AASHTO, there will > be an opportunity to define new TAZs for CTPP data products. Questions > to be answered revolve around how many different TAZ systems should > there be, the cost for developing those systems and the mechanical > process for submitting them. To help define TAZs, discussions with the > CB's Geography Division are underway. > > 2. How will new TAZs be submitted to the Census Bureau (CB) and added > to TIGER? > > The CB has a contract with M-cubed and its subcontract Caliper > Corporation for software development to support the "Participant > Statistical Areas Program" (PSAP). The PSAP includes the tract and > block group definition process. The software being developed for this > program can be modified to accommodate TAZ, SuperTAZ or any other > geographic units that the transportation planning community would like > to have. As a result, it makes sense to have tract, block group, and > the TAZ definition efforts be a coordinated process. Of course the > development of any TAZs are premised on and would be paid for by the > pooled-fund. > > 3. When will the Census Bureau (CB) use the new TAZ definitions to > tabulate ACS data for CTPP? > > Since the CB PSAP to define track and block groups is focused on the > 2010 regular census, tabulations of ACS data issued in 2010 and after > would follow the new geographies. Any earlier products would use > existing 2000 geography. For example, the pooled-fund calls for > small-area tabulations from ACS data using a required 5-year period -- > 2005, '06, '07, '08 and '09. The data would not be released until > 2010-2011 and we have been assured that it would follow 2010 geography. > However, for our first 3-year product (2005, '06 and '07), we have to > use 2000 geographic units and meet the 20,000 population threshold per > zone. > > 4. What is the history of TAZ definition for CTPP? > > For the 1980 and 1990 data tabulations TAZs were restricted to 6 > characters and only one set of TAZs could be defined per region. The > data assigned to these TAZs represented an equivalency process where > MPOs were asked to let the CB know which blocks to assign to which TAZ. > Blocks could not be split and the TAZs really became an aggregation of > blocks and block groups. > > In 2000, a major improvement was made where the TAZs were defined early > and placed in the CB TIGER file. With the TAZs in TIGER the CB was then > able to put the actual data for the area the TAZ represented in the > predetermined TAZs. For the first time the "urban" TAZs became a unique > tabulation geography and not just an aggregation of Census geographical > units. While this new process was adopted for TAZs the equivalency > process remained for those areas that crated state-level TAZs. This was > due to size limitation of the TIGER record and other technical > processing issues. > > 5. WHAT are some items to consider? > > As we look toward the future and ACS related transportation data > products, further TIGER improvements are on the horizon. Inside the CB > the Geography Division is undergoing a major overhaul of its TIGER file > data base. Conceptually, TIGER is moving to something akin to a > relational data base and space limitations are a thing of the past. Not > only can we consider adding more characters to the TAZ field, we can > even talk about having different TAZ zone structures. Assuming the > AASHTO pooled-fund is approved, one of the first tasks will be to focus > on defining TAZs for inclusion into the new TIGER system. As a result, > we need to focus on what we want in terms of TAZs. > > Other items that are nearing the horizon concern the detail data tables > to be included in the various products. The pooled-fund is calling for > a one, three and five year transportation data product. However, before > we work on the specific details of the product design the pooled-fund > must first be approved and funded. > > As Chair of the TRB Urban Data Committee, the sponsoring committee of > the Census Data Subcommittee, I hope to see this list serve used as a > forum to feed these discussions. Currently we have over 550 subscribers > to this list, most who are the active census data users in their MPOs, > states, consulting firms and universities. > > Finally, if you have a question about any of this, please post it to the > list serve. We are at a critical time in terms of getting the > information out to our various users. So please share your comments, > questions and experiences. > > -- > 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) >

18 years, 10 months

[CTPP] 2005 Transportation Profiles now posted on AASHTO webpage

by Murakami

Dear Everyone: We have created a limited set of profile sheets: National, States, a few large cities, and several Metropolitan Areas. The profiles include data from 1990 Census, 2000 Census, and the 2005 American Community Survey. http://ctpp.transportation.org/2005.htm PLEASE READ THE "NOTES" which has more information about "GQ: group quarters" "MOE: Margin of Error," and geographic comparison issues. The Census Bureau advices data users NOT to make direct comparisons between the ACS and decennial Census results because of changes in survey methods. However, one of the main uses of the newly released 2005 ACS is to examine trends from 2000. If your area was included in the sample of counties (about one-third of counties) in the 2000 ACS C2SS, we recommend that you include both 2000 Census and C2SS results when you analyze changes over time for RESIDENCE GEOGRAPHY. You will see in the "highlights" documents attached that we have included two bar charts using this approach. These pages use the 2005 ACS data released on August 29. We will be working on another set of profile sheets using the 2005 ACS data released on October 3. Elaine Murakami on behalf of the CTPP Team

18 years, 10 months

[CTPP] Calculating margins of error for derived estimates for ACS 2005

by Nanda.Srinivasan＠dot.gov

All- In the last few weeks, we have received questions on how to calculate margins of error (MOE) when you add, or subtract, or divide ACS 2005 data. The Census Bureau has some instructions for applying statistical testing to ACS Data posted at http://www.census.gov/acs/www/Products/users_guide/ACS_2005_Statistical_Tes…. Using these instructions, I prepared an MS Excel template for calculating MOE for additions, subtractions, proportions, or percents (please see attached MOE.xls). I am assuming 90% CI for my calculations. There are three worksheets (one for additions/subtractions, one for proportions, and one for percents). <<MOE.xls>> Hope you find these useful. Thanks Nanda Srinivasan 202-366-5021

18 years, 10 months

[CTPP] We Need you Help---PLEASE Comment

by Ed Christopher

This past summer I worked with several TRANSIT planners and developed a research problem statement calling for a "guidebook on using ACS and other census data for transit planning." The official tittle is #32 Census Data for Transit Systems Planning (07-H-03). The problem statement was submitted to the Transit Cooperative Research Program (TCRP) of the National Academies of Sciences (TCRP-http://www4.trb.org/trb/crp.nsf) In trying to find out the status of the proposal I just learned that of all the projects submitted, 41 have passed the initial screening phase and have been recommended for funding consideration. Of the 41 projects, about 10 will be selected and COMMENTS are being sought from the community at large. On October 10-20 the TCRP Oversight and Project Selection (TOPS) Committee will meet to select the FY07 problem statements. Specifically, comments are sought on the following aspects of the individual problem statements: 1) the merits of the problem statement and 2) any ongoing work of which you are aware that would create a potential duplication of effort. Your comments would then be made available to the TOPS Committee at the October meeting. Comments will be accepted through Sunday, October 15, 2006. To submit comments, send an email to tcrp(a)nas.edu with the subject "Comments on Problem Statements." Be sure to identify the problem statement(s) being commented on. Here is the URL to the 41 problem statements and further information on call for comments. http://www4.trb.org/trb/crp.nsf/reference/boilerplate/Attachments/$file/200… Feel free to call me with any questions, etc. But most of all please comment. -- Ed Christopher 708-283-3534 (V) 708-574-8131 (cell) FHWA RC-TST-PLN 19900 Governors Dr Olympia Fields, IL 60461

18 years, 10 months

Re: [CTPP] CTPP Discussion Issues

by ed christopher

Zak--I hope that it is OK that I am responding to the whole list serve. For the 5-year product the thinking is that it could be similar to prior data releases (2000, 1990 and 1980). However, you are right the disclosure rules played havoc with several of the 2000 tables. Since we can't get rid of the disclosure rules that is why you are hearing so much talk about the potential for some synthesized data. I totally agree that larger zonal data aggregations really will not do much for transit. In all honesty it would help if the transit planning community could assert itself and become a little more engaged at the front end of the process. There was (is) a TCRP proposal in the hopper seeking to do a guidebook for transit planning using various census data products but I have not heard how it came out in the selection process. I believe that the committee that picks the projects was to meet sometime in the middle of September. Maybe someone on this knows the status. In thinking about all of this (and showing my age) I keep hearing Mick Jagger inside my head saying "you can't always get what you want, but if you try sometimes, you'll find you get what you need" Thanks for the post "Zakaria, Thabet" wrote: > Hi Ed: > > Excellent CTPP discussion issues. However, I have several questions and > comments for your consideration. Are we going to have TAZ-to-TAZ data in > 2010-2011, similar to Part III of the 2000 package? If yes, are the data > going to be subject to the CB's disclosure avoidance process? As you > know, the loss of data due to the threshold requirement in 2000 was > significant and the data became totally useless. TAZ-to-TAZ data are > required for most projects in transportation planning. Geographic units > larger than TAZs, such as the 20,000 population per zone, super zones or > large districts would not provide the data needed to plan individual > transportation facilities, such as transit routes. > > According to the ACS program, only the five-year transportation data > products at the zonal level would be useful. The one-year products would > be useful after 2010 because of previous accumulation of data. Based on > our evaluation of 2005 ACS data, the first 3-year product (2005, 2006 > and 2007) would be useful for geographic units larger than 65,000 > population threshold per zone, not 20,000 as proposed by the CB. The > 2005 ACS sample was not large enough to even produce accurate estimates > for all means of transportation to work for Gloucester County, NJ > (277,000 people). > > Thabet Zakaria > Deputy Director, Technical Services > Delaware Valley Regional Planning Commission > Phone: 215-238-2885 > Email: tzakaria(a)dvrpc.org > Fax: 215-592-9125 > > -----Original Message----- > From: ctpp-news-bounces(a)chrispy.net > [mailto:ctpp-news-bounces(a)chrispy.net] On Behalf Of ed christopher > Sent: Monday, October 02, 2006 11:19 AM > To: ctpp-news maillist > Subject: [CTPP] CTPP Discussion Issues > > During the past few months I have received several questions regarding > the need for small area, Traffic Analysis Zone (TAZ), data from the > American Community Survey (ACS) so I thought I would provide an update. > > GENERAL UPDATE ON CTPP > > There are two groups that are working on census data needs for the > transportation community. > > First there is the long-standing CTPP Working Group that meets monthly > and has been responsible for the content of the 1980, 1990 and 2000 data > packages. Although the precise membership of this working group has > changed over time it has generally been made up of US DOT staff, Census > Bureau (CB) staff, Dave Clawson from AASHTO, and members of > Transportation Research Board (TRB) committees. The work of the CTPP > Working Group tends to focus on the highly technical aspects of the > data. Since 1997, this group has met at least once a month and has been > chaired by Elaine Murakami of FHWA. > > Working in concert with the CTPP Working Group, the AASHTO Standing > Committee on Planning (SCOP) last August (2005) initiated a broader > based Committee called the SCOP Census Work Group. Jonette Kreideweis > of the Minnesota DOT chairs this group. Its main focus has been on > issues that transportation planners need to know to use the ACS and it > has been instrumental in recognizing that a "family" of new data > products will be needed. In June the Work Group proposed a pooled-fund > project that includes data products, research, training, and technical > support. The pooled-fund is currently before SCOP and I hope that it > will be approved by AASHTO in October. The pooled-fund builds upon the > experience gained from the 1990 and 2000 pooled-fund projects and > details on it can be found on the TRB Subcommittee on Census Data > website at http://trbcensus.com/SCOP/ > > TAZ DEFINITION for ACS > > 1. Will MPOs and State DOTs be asked to submit new TAZs? > > Assuming that a new CTPP pooled-fund is approved by AASHTO, there will > be an opportunity to define new TAZs for CTPP data products. Questions > to be answered revolve around how many different TAZ systems should > there be, the cost for developing those systems and the mechanical > process for submitting them. To help define TAZs, discussions with the > CB's Geography Division are underway. > > 2. How will new TAZs be submitted to the Census Bureau (CB) and added > to TIGER? > > The CB has a contract with M-cubed and its subcontract Caliper > Corporation for software development to support the "Participant > Statistical Areas Program" (PSAP). The PSAP includes the tract and > block group definition process. The software being developed for this > program can be modified to accommodate TAZ, SuperTAZ or any other > geographic units that the transportation planning community would like > to have. As a result, it makes sense to have tract, block group, and > the TAZ definition efforts be a coordinated process. Of course the > development of any TAZs are premised on and would be paid for by the > pooled-fund. > > 3. When will the Census Bureau (CB) use the new TAZ definitions to > tabulate ACS data for CTPP? > > Since the CB PSAP to define track and block groups is focused on the > 2010 regular census, tabulations of ACS data issued in 2010 and after > would follow the new geographies. Any earlier products would use > existing 2000 geography. For example, the pooled-fund calls for > small-area tabulations from ACS data using a required 5-year period -- > 2005, '06, '07, '08 and '09. The data would not be released until > 2010-2011 and we have been assured that it would follow 2010 geography. > However, for our first 3-year product (2005, '06 and '07), we have to > use 2000 geographic units and meet the 20,000 population threshold per > zone. > > 4. What is the history of TAZ definition for CTPP? > > For the 1980 and 1990 data tabulations TAZs were restricted to 6 > characters and only one set of TAZs could be defined per region. The > data assigned to these TAZs represented an equivalency process where > MPOs were asked to let the CB know which blocks to assign to which TAZ. > Blocks could not be split and the TAZs really became an aggregation of > blocks and block groups. > > In 2000, a major improvement was made where the TAZs were defined early > and placed in the CB TIGER file. With the TAZs in TIGER the CB was then > able to put the actual data for the area the TAZ represented in the > predetermined TAZs. For the first time the "urban" TAZs became a unique > tabulation geography and not just an aggregation of Census geographical > units. While this new process was adopted for TAZs the equivalency > process remained for those areas that crated state-level TAZs. This was > due to size limitation of the TIGER record and other technical > processing issues. > > 5. WHAT are some items to consider? > > As we look toward the future and ACS related transportation data > products, further TIGER improvements are on the horizon. Inside the CB > the Geography Division is undergoing a major overhaul of its TIGER file > data base. Conceptually, TIGER is moving to something akin to a > relational data base and space limitations are a thing of the past. Not > only can we consider adding more characters to the TAZ field, we can > even talk about having different TAZ zone structures. Assuming the > AASHTO pooled-fund is approved, one of the first tasks will be to focus > on defining TAZs for inclusion into the new TIGER system. As a result, > we need to focus on what we want in terms of TAZs. > > Other items that are nearing the horizon concern the detail data tables > to be included in the various products. The pooled-fund is calling for > a one, three and five year transportation data product. However, before > we work on the specific details of the product design the pooled-fund > must first be approved and funded. > > As Chair of the TRB Urban Data Committee, the sponsoring committee of > the Census Data Subcommittee, I hope to see this list serve used as a > forum to feed these discussions. Currently we have over 550 subscribers > to this list, most who are the active census data users in their MPOs, > states, consulting firms and universities. > > Finally, if you have a question about any of this, please post it to the > list serve. We are at a critical time in terms of getting the > information out to our various users. So please share your comments, > questions and experiences. > > -- > 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) > > _______________________________________________ > ctpp-news mailing list > ctpp-news(a)chrispy.net > http://www.chrispy.net/mailman/listinfo/ctpp-news -- 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)

18 years, 10 months

[CTPP] CTPP Discussion Issues

by ed christopher

During the past few months I have received several questions regarding the need for small area, Traffic Analysis Zone (TAZ), data from the American Community Survey (ACS) so I thought I would provide an update. GENERAL UPDATE ON CTPP There are two groups that are working on census data needs for the transportation community. First there is the long-standing CTPP Working Group that meets monthly and has been responsible for the content of the 1980, 1990 and 2000 data packages. Although the precise membership of this working group has changed over time it has generally been made up of US DOT staff, Census Bureau (CB) staff, Dave Clawson from AASHTO, and members of Transportation Research Board (TRB) committees. The work of the CTPP Working Group tends to focus on the highly technical aspects of the data. Since 1997, this group has met at least once a month and has been chaired by Elaine Murakami of FHWA. Working in concert with the CTPP Working Group, the AASHTO Standing Committee on Planning (SCOP) last August (2005) initiated a broader based Committee called the SCOP Census Work Group. Jonette Kreideweis of the Minnesota DOT chairs this group. Its main focus has been on issues that transportation planners need to know to use the ACS and it has been instrumental in recognizing that a family of new data products will be needed. In June the Work Group proposed a pooled-fund project that includes data products, research, training, and technical support. The pooled-fund is currently before SCOP and I hope that it will be approved by AASHTO in October. The pooled-fund builds upon the experience gained from the 1990 and 2000 pooled-fund projects and details on it can be found on the TRB Subcommittee on Census Data website at http://trbcensus.com/SCOP/ TAZ DEFINITION for ACS 1. Will MPOs and State DOTs be asked to submit new TAZs? Assuming that a new CTPP pooled-fund is approved by AASHTO, there will be an opportunity to define new TAZs for CTPP data products. Questions to be answered revolve around how many different TAZ systems should there be, the cost for developing those systems and the mechanical process for submitting them. To help define TAZs, discussions with the CBs Geography Division are underway. 2. How will new TAZs be submitted to the Census Bureau (CB) and added to TIGER? The CB has a contract with M-cubed and its subcontract Caliper Corporation for software development to support the Participant Statistical Areas Program (PSAP). The PSAP includes the tract and block group definition process. The software being developed for this program can be modified to accommodate TAZ, SuperTAZ or any other geographic units that the transportation planning community would like to have. As a result, it makes sense to have tract, block group, and the TAZ definition efforts be a coordinated process. Of course the development of any TAZs are premised on and would be paid for by the pooled-fund. 3. When will the Census Bureau (CB) use the new TAZ definitions to tabulate ACS data for CTPP? Since the CB PSAP to define track and block groups is focused on the 2010 regular census, tabulations of ACS data issued in 2010 and after would follow the new geographies. Any earlier products would use existing 2000 geography. For example, the pooled-fund calls for small-area tabulations from ACS data using a required 5-year period -- 2005, 06, 07, 08 and 09. The data would not be released until 2010-2011 and we have been assured that it would follow 2010 geography. However, for our first 3-year product (2005, 06 and 07), we have to use 2000 geographic units and meet the 20,000 population threshold per zone. 4. What is the history of TAZ definition for CTPP? For the 1980 and 1990 data tabulations TAZs were restricted to 6 characters and only one set of TAZs could be defined per region. The data assigned to these TAZs represented an equivalency process where MPOs were asked to let the CB know which blocks to assign to which TAZ. Blocks could not be split and the TAZs really became an aggregation of blocks and block groups. In 2000, a major improvement was made where the TAZs were defined early and placed in the CB TIGER file. With the TAZs in TIGER the CB was then able to put the actual data for the area the TAZ represented in the predetermined TAZs. For the first time the urban TAZs became a unique tabulation geography and not just an aggregation of Census geographical units. While this new process was adopted for TAZs the equivalency process remained for those areas that crated state-level TAZs. This was due to size limitation of the TIGER record and other technical processing issues. 5. WHAT are some items to consider? As we look toward the future and ACS related transportation data products, further TIGER improvements are on the horizon. Inside the CB the Geography Division is undergoing a major overhaul of its TIGER file data base. Conceptually, TIGER is moving to something akin to a relational data base and space limitations are a thing of the past. Not only can we consider adding more characters to the TAZ field, we can even talk about having different TAZ zone structures. Assuming the AASHTO pooled-fund is approved, one of the first tasks will be to focus on defining TAZs for inclusion into the new TIGER system. As a result, we need to focus on what we want in terms of TAZs. Other items that are nearing the horizon concern the detail data tables to be included in the various products. The pooled-fund is calling for a one, three and five year transportation data product. However, before we work on the specific details of the product design the pooled-fund must first be approved and funded. As Chair of the TRB Urban Data Committee, the sponsoring committee of the Census Data Subcommittee, I hope to see this list serve used as a forum to feed these discussions. Currently we have over 550 subscribers to this list, most who are the active census data users in their MPOs, states, consulting firms and universities. Finally, if you have a question about any of this, please post it to the list serve. We are at a critical time in terms of getting the information out to our various users. So please share your comments, questions and experiences. -- 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)

18 years, 10 months

RE: [CTPP] October 3 is the next scheduled release ofACStablesincluding PLACE OF WORK!

by Richard Lin

Dear Tom, Just ask the Census Bureau Data Users Division for qualifications to be included in the Pre-Embargo List. As I (as FSCPE and REAC members) know, many organizations such as SDC, FSCPE, news/press organizations, and many others are on the lists by signing a News Release Embargo Agreement. If you have very good reasons (representing many data users) to be included, you should pursue. Just get to the Embargo website from the Census Bureau's homepage and contact the person in charge. Good luck. ________________________________ Richard Lin, Ph.D. Demographer Colorado Department of Local Affairs Division of Local Government 1313 Sherman Street, Room 521 Denver, CO 80203 Phone: (303)866-4989 Fax:: (303)866-2660 richard.lin(a)state.co.us www.DOLA.Colorado.Gov >>> "Tom Reinauer" <treinauer(a)smrpc.org> 10/2/2006 7:35 AM >>> I agree with Ed. This is a problem, and I remember commenting about it extensively following the 2000 Census data started being released. Perhaps there's an opportunity to collectively ask the appropriate agency/agencies to see if there is a way that professionals can receive the data prior to or at the same time as the press. I have since forgotten about how/why this embargo thing occurs, but it would save us a lot of time explaining and correcting things after-the- fact. --Tom Tom Reinauer, Transportation Director Southern Maine RPC & Kittery Area MPO 21 Bradeen St. Suite 304 Springvale, ME 04083 (207)324-2952 Ext. 18 (207)324-2958 fax treinauer(a)smrpc.org www.smrpc.org -----Original Message----- From: ed christopher [mailto:edc(a)berwyned.com] Sent: Thursday, September 28, 2006 11:11 AM To: Alan Pisarski Cc: Srinivasan, Nanda; ctpp-news maillist; 'Murakami,Elaine'; North,Joel; Phil Salopek Subject: Re: [CTPP] October 3 is the next scheduled release ofACStablesincluding PLACE OF WORK! This has always been the issue. The press gets the data early as embargoed and then the transportation folks get torpedoed and don't have a chance to respond because they haven't seen the data. Case in point. The Atlanta Journal Constitution ran an article about one county leading the nation with a 51 minute travel time. Well after the story broke Joel North from GDOT and Nandu Srinivasan used PUMs to learn the data looked funny. There were way too many 150 minute type commutes. The data did not make sense and with sampling things can happen. Elaine Murakami then found out from Phil that indeed something was wrong. The CB had a bad coder survey taker at the front end, going through retraining and trying to figure out how to deal with the data.. The point however, is if the "public agency" transportation community had the data when the press had it we may have been able to inform what became a very misleading article. Another point--People do need to look at the data. I have playing with the rank of all 775 counties that have data by their mean travel time. American Factfinder has a lot on it. The article can be found at (You do have to register for a fee) 51.6 MINUTES :Commute time report stumps Coweta officials Date: September 7, 2006 http://nl.newsbank.com/nojavascript.html Land of the long commute: Georgia is No. 1 in counties with time-wasting trips to work. The sprawl makes homes affordable, but the crawl drives down the quality of life. Date: August 31, 2006 http://nl.newsbank.com/nojavascript.html Alan Pisarski wrote: > USA Today has the data and is planning a fairly major play on the > release date. AEP > _____ > > From: ctpp-news-bounces(a)chrispy.net > [mailto:ctpp-news-bounces(a)chrispy.net] > On Behalf Of Murakami, Elaine > Sent: Tuesday, September 26, 2006 7:46 PM > To: ctpp-news(a)chrispy.net > Subject: [CTPP] October 3 is the next scheduled release of ACS > tablesincluding PLACE OF WORK! > > How time flies! Just when you thought you were getting a handle on > the journey-to-work data from the 2005 ACS, the next round of data > will released! The next set will include Place of Work tabulations. > >From the CTPP world, these are like "CTPP Part 2" tables, where the tabulation is by > place-of-work, rather than place-of-residence. Since the 2005 ACS included > ALL counties in the sample, the place-of-work tabulations should look > much better than the 2004 ACS place-of-work tabulations (about > one-third of counties were included in the sample). > > Don't forget: > > 1. 2005 ACS does not include Group Quarters population. That is, > areas with large military installations and/or college dormitories > should expect considerable differences when comparing to Census 2000 > results. > > 2. The data are collected over all 12 months, therefore areas with > seasonal shifts are likely to see the greatest differences when > comparing to Census 2000 results. > > Good luck! Nanda Srinivasan, Ed Christopher and I are trying to wrap > up our new Profile sheets using the 2005 ACS Place-of-Residence > tables, but we have had a lot of work on calculating Margins of Error > and incorporating the results into the tables. > > Elaine Murakami > FHWA Office of Planning > 206-220-4460 (in Seattle) -- Ed Christopher FHWA Resource Center 19900 Governors Drive Olympia Fields, Illinois 60461 708-283-3534 (v) 708-283-3501 (f) 708-574-8131 (cell) _______________________________________________ ctpp-news mailing list ctpp-news(a)chrispy.net http://www.chrispy.net/mailman/listinfo/ctpp-news _______________________________________________ ctpp-news mailing list ctpp-news(a)chrispy.net http://www.chrispy.net/mailman/listinfo/ctpp-news

18 years, 10 months

RE: [CTPP] October 3 is the next scheduled release ofACStablesincluding PLACE OF WORK!

by Tom Reinauer

I agree with Ed. This is a problem, and I remember commenting about it extensively following the 2000 Census data started being released. Perhaps there's an opportunity to collectively ask the appropriate agency/agencies to see if there is a way that professionals can receive the data prior to or at the same time as the press. I have since forgotten about how/why this embargo thing occurs, but it would save us a lot of time explaining and correcting things after-the- fact. --Tom Tom Reinauer, Transportation Director Southern Maine RPC & Kittery Area MPO 21 Bradeen St. Suite 304 Springvale, ME 04083 (207)324-2952 Ext. 18 (207)324-2958 fax treinauer(a)smrpc.org www.smrpc.org -----Original Message----- From: ed christopher [mailto:edc(a)berwyned.com] Sent: Thursday, September 28, 2006 11:11 AM To: Alan Pisarski Cc: Srinivasan, Nanda; ctpp-news maillist; 'Murakami,Elaine'; North,Joel; Phil Salopek Subject: Re: [CTPP] October 3 is the next scheduled release ofACStablesincluding PLACE OF WORK! This has always been the issue. The press gets the data early as embargoed and then the transportation folks get torpedoed and don't have a chance to respond because they haven't seen the data. Case in point. The Atlanta Journal Constitution ran an article about one county leading the nation with a 51 minute travel time. Well after the story broke Joel North from GDOT and Nandu Srinivasan used PUMs to learn the data looked funny. There were way too many 150 minute type commutes. The data did not make sense and with sampling things can happen. Elaine Murakami then found out from Phil that indeed something was wrong. The CB had a bad coder survey taker at the front end, going through retraining and trying to figure out how to deal with the data.. The point however, is if the "public agency" transportation community had the data when the press had it we may have been able to inform what became a very misleading article. Another point--People do need to look at the data. I have playing with the rank of all 775 counties that have data by their mean travel time. American Factfinder has a lot on it. The article can be found at (You do have to register for a fee) 51.6 MINUTES :Commute time report stumps Coweta officials Date: September 7, 2006 http://nl.newsbank.com/nojavascript.html Land of the long commute: Georgia is No. 1 in counties with time-wasting trips to work. The sprawl makes homes affordable, but the crawl drives down the quality of life. Date: August 31, 2006 http://nl.newsbank.com/nojavascript.html Alan Pisarski wrote: > USA Today has the data and is planning a fairly major play on the > release date. AEP > _____ > > From: ctpp-news-bounces(a)chrispy.net > [mailto:ctpp-news-bounces(a)chrispy.net] > On Behalf Of Murakami, Elaine > Sent: Tuesday, September 26, 2006 7:46 PM > To: ctpp-news(a)chrispy.net > Subject: [CTPP] October 3 is the next scheduled release of ACS > tablesincluding PLACE OF WORK! > > How time flies! Just when you thought you were getting a handle on > the journey-to-work data from the 2005 ACS, the next round of data > will released! The next set will include Place of Work tabulations. > >From the CTPP world, these are like "CTPP Part 2" tables, where the tabulation is by > place-of-work, rather than place-of-residence. Since the 2005 ACS included > ALL counties in the sample, the place-of-work tabulations should look > much better than the 2004 ACS place-of-work tabulations (about > one-third of counties were included in the sample). > > Don't forget: > > 1. 2005 ACS does not include Group Quarters population. That is, > areas with large military installations and/or college dormitories > should expect considerable differences when comparing to Census 2000 > results. > > 2. The data are collected over all 12 months, therefore areas with > seasonal shifts are likely to see the greatest differences when > comparing to Census 2000 results. > > Good luck! Nanda Srinivasan, Ed Christopher and I are trying to wrap > up our new Profile sheets using the 2005 ACS Place-of-Residence > tables, but we have had a lot of work on calculating Margins of Error > and incorporating the results into the tables. > > Elaine Murakami > FHWA Office of Planning > 206-220-4460 (in Seattle) -- Ed Christopher FHWA Resource Center 19900 Governors Drive Olympia Fields, Illinois 60461 708-283-3534 (v) 708-283-3501 (f) 708-574-8131 (cell) _______________________________________________ ctpp-news mailing list ctpp-news(a)chrispy.net http://www.chrispy.net/mailman/listinfo/ctpp-news

18 years, 10 months

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