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2. REENGINEERING THE DECENNIAL CENSUS OVERVIEW. MAF/TIGER Enhancements Program 2010 Census
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2. 2 REENGINEERING THE DECENNIAL CENSUS OVERVIEW After the 2000 Census, user complaints escalated with respect to the need for more timely socio economic data than every 10 years. There were also problems with the efficiency of tying census responses to physical locations, as well as the ability to draw robust samples for census related surveys based on the most current and correct address lists. Many of the complaints came from Congress, so the Census Bureau embarked on an ambitious quest to address these concerns.
A three pronged approach was developed to: 1) better tie addresses and street features together, 2) develop new methods to conduct the next decennial census, both more efficiently and cost effectively, and 3) to replace the sample portion of the 2010 census with a new collection method which would provide comparable demographic, socio-economic and housing statistics on an annual basis.
After the 2000 Census, user complaints escalated with respect to the need for more timely socio economic data than every 10 years. There were also problems with the efficiency of tying census responses to physical locations, as well as the ability to draw robust samples for census related surveys based on the most current and correct address lists. Many of the complaints came from Congress, so the Census Bureau embarked on an ambitious quest to address these concerns.
A three pronged approach was developed to: 1) better tie addresses and street features together, 2) develop new methods to conduct the next decennial census, both more efficiently and cost effectively, and 3) to replace the sample portion of the 2010 census with a new collection method which would provide comparable demographic, socio-economic and housing statistics on an annual basis.
3. 3 REENGINEERING THE DECENNIAL CENSUS OVERVIEW The MAF/TIGER Enhancements ProgramThe MAF/TIGER Enhancements Program
4. 4 MAF/TIGER Enhancements Program The MAF, or Master Address File, was designed to be a complete and current list of all addresses and locations where people live or work, covering an estimated 115 million residences, as well as 60 million businesses and other structures in the U.S. It is used as the sampling base for many Census program as well as for disseminating the 2010 decennial census questionnaire. Later in this presentation I will discuss a census program called LUCA which will be used to update and correct the MAF addresses for Alaska.
The TIGER®, or Topologically Integrated Geographic Encoding and Referencing portion of the project, is a digital database that identifies the type, location and name of streets, rivers, railroads and other geographic features, and geospatially defines their relationships to each other, to the MAF addresses, and to numerous other entities. Earlier this decade, a major contract was awarded to geospatially control and correct the locations of many of the features in TIGER. The results of this work will vastly improve the use of census data in conjunction with Alaska’s census maps, as the features will now allign with the mapping data of many of our local government’s.
The MAF, or Master Address File, was designed to be a complete and current list of all addresses and locations where people live or work, covering an estimated 115 million residences, as well as 60 million businesses and other structures in the U.S. It is used as the sampling base for many Census program as well as for disseminating the 2010 decennial census questionnaire. Later in this presentation I will discuss a census program called LUCA which will be used to update and correct the MAF addresses for Alaska.
The TIGER®, or Topologically Integrated Geographic Encoding and Referencing portion of the project, is a digital database that identifies the type, location and name of streets, rivers, railroads and other geographic features, and geospatially defines their relationships to each other, to the MAF addresses, and to numerous other entities. Earlier this decade, a major contract was awarded to geospatially control and correct the locations of many of the features in TIGER. The results of this work will vastly improve the use of census data in conjunction with Alaska’s census maps, as the features will now allign with the mapping data of many of our local government’s.
5. 5 MAF/TIGER Enhancements Program This slide gives an example of the kinds of features and boundaries contained within the TIGER file which are available to make maps of the State’s communities. We have been populating our Census and Geographic Information Network or CGIN web site with these maps along with series of other geographic areas.
This slide gives an example of the kinds of features and boundaries contained within the TIGER file which are available to make maps of the State’s communities. We have been populating our Census and Geographic Information Network or CGIN web site with these maps along with series of other geographic areas.
6. 6 MAF/TIGER Enhancements Program This next slide shows the more settled portion of Cold Bay and presents an example of the amount of control work necessary to bring the TIGER roads, and… features like the airport, into conformity with the real roads and airport on the ground. This is referred to as ground truthing.
The colored lines are from the Census TIGER data, and have been overlaid on satellite imagery. As you can see there is a difference in location of the colored lines compared to where they should be located. Clearly a substantial amount of work is involved just to bring this one small area into conformity. Vast portions of the State have had to go through similar correcting including Anchorage, Fairbanks, Mat-Su and Juneau to mention the larger populated areas.
Once these files are completed and available to the public, the usefulness of census tabulation areas and the related census data will increase even more as we will be able to overlay this information on imagery and provide an even better indepth look at the state’s communities. It also will make identifying, updating and maintaining road features and housing addresses much easier.
This next slide shows the more settled portion of Cold Bay and presents an example of the amount of control work necessary to bring the TIGER roads, and… features like the airport, into conformity with the real roads and airport on the ground. This is referred to as ground truthing.
The colored lines are from the Census TIGER data, and have been overlaid on satellite imagery. As you can see there is a difference in location of the colored lines compared to where they should be located. Clearly a substantial amount of work is involved just to bring this one small area into conformity. Vast portions of the State have had to go through similar correcting including Anchorage, Fairbanks, Mat-Su and Juneau to mention the larger populated areas.
Once these files are completed and available to the public, the usefulness of census tabulation areas and the related census data will increase even more as we will be able to overlay this information on imagery and provide an even better indepth look at the state’s communities. It also will make identifying, updating and maintaining road features and housing addresses much easier.
7. 7 REENGINEERING THE DECENNIAL CENSUS OVERVIEW Moving on to the 2nd major reengineered component…….The 2010 census will be a short form only census. What this means is, the long form portion of the census questionnaire, which historically collected the well used socio economic data every 10 years, has been replaced by the ACS. Decoupling the short form and long form allows the Census Bureau to focus efforts on the constitutional requirements to produce a count of the resident population, to employ technology which will improve efficiencies, to improve the overall census accuracy by increasing the coverage rate, and to reduce the overall costs associated with a decennial census.
Moving on to the 2nd major reengineered component…….The 2010 census will be a short form only census. What this means is, the long form portion of the census questionnaire, which historically collected the well used socio economic data every 10 years, has been replaced by the ACS. Decoupling the short form and long form allows the Census Bureau to focus efforts on the constitutional requirements to produce a count of the resident population, to employ technology which will improve efficiencies, to improve the overall census accuracy by increasing the coverage rate, and to reduce the overall costs associated with a decennial census.
8. 8 2010 Census – short form subjects While we expect the questions asked in Census 2010 to be very similar to what was asked on the short form in Census 2000, Section 141 (f) of the Census Act requires that not later than 3 years before the next census the subjects to be included on that census be submitted to Congress.
The 6 items listed on this slide cover in total the subjects for the 2010 Census.
In advance of providing these subjects to Congress, which was done on March 30 of this year, the U.S. Census Bureau asked federal agencies to provide information on their data needs, so that only necessary data are collected, as opposed to data that could be acquired by other means. The Office of Management and Budget facilitates the process to validate current uses of census data by determining whether subjects and questions are necessary and identifying new subjects for which questions are required.
The Census Act also requires that not later than two years before the Census date, the actual census questions be submitted to Congress. According to the census bureau they are ready to submit those questions by March 31, 2008, …..and that it will take less than 10 minutes to complete the 2010 Census, which will be one of the shortest and easiest to complete since the nation’s first census in 1790.
While we expect the questions asked in Census 2010 to be very similar to what was asked on the short form in Census 2000, Section 141 (f) of the Census Act requires that not later than 3 years before the next census the subjects to be included on that census be submitted to Congress.
The 6 items listed on this slide cover in total the subjects for the 2010 Census.
In advance of providing these subjects to Congress, which was done on March 30 of this year, the U.S. Census Bureau asked federal agencies to provide information on their data needs, so that only necessary data are collected, as opposed to data that could be acquired by other means. The Office of Management and Budget facilitates the process to validate current uses of census data by determining whether subjects and questions are necessary and identifying new subjects for which questions are required.
The Census Act also requires that not later than two years before the Census date, the actual census questions be submitted to Congress. According to the census bureau they are ready to submit those questions by March 31, 2008, …..and that it will take less than 10 minutes to complete the 2010 Census, which will be one of the shortest and easiest to complete since the nation’s first census in 1790.
9. 9 2010 Census – timeline On the Census Bureau’s webpage under Timeline of Activities, there are only these 3 dates: March 2010 when the 2010 census questionnaires will be sent out; April to June 2010 when non response households are contacted by census workers ; and December 31, 2010 when the U.S population totals are due to the President.
I have prepared a time line based on census participant preparation programs that are, or will be, taking place here in Alaska between now and 2010. On the Census Bureau’s webpage under Timeline of Activities, there are only these 3 dates: March 2010 when the 2010 census questionnaires will be sent out; April to June 2010 when non response households are contacted by census workers ; and December 31, 2010 when the U.S population totals are due to the President.
I have prepared a time line based on census participant preparation programs that are, or will be, taking place here in Alaska between now and 2010.
10. 10 2010 Census – timeline of participant programs in Alaska There are 5 programs currently underway, or soon to begin which our office takes a primary role in, through either coordinating, reviewing or assisting local communities with their work, or often doing the program work itself for those areas which contain no local government within the unorganized borough…or census areas. Many of these programs will invite local participation, and it is important that each local government eligible to participate, does so as the accuracy of their 2010 population counts will affect future funding for schools, clinics, transportation issues, headstart programs, and even state revenue sharing.
There are 5 programs currently underway, or soon to begin which our office takes a primary role in, through either coordinating, reviewing or assisting local communities with their work, or often doing the program work itself for those areas which contain no local government within the unorganized borough…or census areas. Many of these programs will invite local participation, and it is important that each local government eligible to participate, does so as the accuracy of their 2010 population counts will affect future funding for schools, clinics, transportation issues, headstart programs, and even state revenue sharing.
11. 11 2010 Census – timeline of participant programs in Alaska I’ll begin with the 2010 Census Redistricting Data Program whose cycle spans from 2004 to 2014.
I’ll begin with the 2010 Census Redistricting Data Program whose cycle spans from 2004 to 2014.
12. 12 2010 Census – timeline of participant programs in Alaska Public Law (P.L.) 94-171, enacted by Congress in December 1975, requires the Census Bureau to provide state legislatures with small area census population tabulations necessary for legislative redistricting. The Census Redistricting Data Program provides states the opportunity to delineate voting or precinct boundaries and state legislative districts, and to suggest census block boundaries for use in the 2010 Census redistricting data tabulations.
To date we have completed Phase 1, where we provided a census block based version of our current legislative district plan to the Census Bureau.
Phase II allows states to provide their precinct boundaries and names to the Census Bureau along with any new features which we would like to have used as census tabulation blocks for the 2010 Census. Our office will, as it did in 1990 and 2000, work with the Division of Elections to recreate all of the state’s precincts based on census block geography. This has been a fairly intensive project in past decades, but we are hoping the newly controlled census geographic data will improve the efficiency of this work.
Phase 3 compels the state’s redistricting work. This is when the Census Bureau delivers geographic products and population totals to the governor and majority and minority leaders of each state, no later than April 1, 2011, as mandated by P.L. 94-171. Alaska’s 90 day redistricting time frame goes into effect upon receipt of these census files.
Phases 4 and 5 take place post the census and are self explanatory.Public Law (P.L.) 94-171, enacted by Congress in December 1975, requires the Census Bureau to provide state legislatures with small area census population tabulations necessary for legislative redistricting. The Census Redistricting Data Program provides states the opportunity to delineate voting or precinct boundaries and state legislative districts, and to suggest census block boundaries for use in the 2010 Census redistricting data tabulations.
To date we have completed Phase 1, where we provided a census block based version of our current legislative district plan to the Census Bureau.
Phase II allows states to provide their precinct boundaries and names to the Census Bureau along with any new features which we would like to have used as census tabulation blocks for the 2010 Census. Our office will, as it did in 1990 and 2000, work with the Division of Elections to recreate all of the state’s precincts based on census block geography. This has been a fairly intensive project in past decades, but we are hoping the newly controlled census geographic data will improve the efficiency of this work.
Phase 3 compels the state’s redistricting work. This is when the Census Bureau delivers geographic products and population totals to the governor and majority and minority leaders of each state, no later than April 1, 2011, as mandated by P.L. 94-171. Alaska’s 90 day redistricting time frame goes into effect upon receipt of these census files.
Phases 4 and 5 take place post the census and are self explanatory.
13. 13 2010 Census – timeline of participant programs in Alaska The Local Update of Census Addresses begins this year and runs to 2010.
The Local Update of Census Addresses begins this year and runs to 2010.
14. 14 2010 Census – timeline of participant programs in Alaska The LUCA Program was developed by the U.S. Census Bureau to meet the requirements of the Census Address List Improvement Act of 1994, P.L. 103-430. Under this voluntary Program, participating governments may review the Census Bureau’s confidential list of individual housing addresses and provide to the Census Bureau address additions, corrections, deletions, and/or the identification of corrected address counts for census blocks. The results of this program are the basis for the address list used to deliver the 2010 Census questionnaire.
Only local governments with city style addresses are eligible to participate in LUCA as well as those boroughs whom contain eligible cities, and the State of Alaska, which can review or participate for any of the eligible areas. The LUCA Program was developed by the U.S. Census Bureau to meet the requirements of the Census Address List Improvement Act of 1994, P.L. 103-430. Under this voluntary Program, participating governments may review the Census Bureau’s confidential list of individual housing addresses and provide to the Census Bureau address additions, corrections, deletions, and/or the identification of corrected address counts for census blocks. The results of this program are the basis for the address list used to deliver the 2010 Census questionnaire.
Only local governments with city style addresses are eligible to participate in LUCA as well as those boroughs whom contain eligible cities, and the State of Alaska, which can review or participate for any of the eligible areas.
15. 15 2010 Census – timeline of participant programs in Alaska This slide gives a visual by using purple shaded areas or purple dots to depict the cities and boroughs which are fully eligible to take part in the LUCA program. The green shaded areas are those boroughs which contain a city eligible for LUCA, and the borough’s participation is limited to only that city. The remainder of the State does not meet the requirements for the program.
Letters from the census bureau inviting the State’s cities went out in August, and we are expecting the remaining letters inviting the other participants to arrive soon.
Our CGIN program will again monitor and assist with this work. We have training workshops scheduled for late October.
This slide gives a visual by using purple shaded areas or purple dots to depict the cities and boroughs which are fully eligible to take part in the LUCA program. The green shaded areas are those boroughs which contain a city eligible for LUCA, and the borough’s participation is limited to only that city. The remainder of the State does not meet the requirements for the program.
Letters from the census bureau inviting the State’s cities went out in August, and we are expecting the remaining letters inviting the other participants to arrive soon.
Our CGIN program will again monitor and assist with this work. We have training workshops scheduled for late October.
16. 16 2010 Census – timeline of participant programs in Alaska The U.S. Census Bureau conducts the Boundary and Annexation Survey or BAS annually to collect information about legally defined geographic areas. The BAS is used to update information about the legal boundaries and names of all governmental units in the United States.
The Census Bureau uses the boundary information collected in the BAS to tabulate data for various censuses and surveys, such as the American Community Survey and other Census Bureau programs, such as the Population Estimates Program. Title 13, United States Code authorizes this voluntary survey. Up until 1998, the BAS was sent out to each city and borough in Alaska for their review.
During our work with the census bureau’s geographic programs in the early 1990’s, however, we discovered that the level of accuracy of the boundaries of all the State’s cities and boroughs in the census TIGER file varied too much, so we proposed an effort to consolidate the BAS work and funnel it through our office so we could ensure that the boundaries of each and every city were correctly represented. But the census bureau only recognized the Local Boundary Commission as the state level entity for providing that review, in lieu of each individual city, due to state statute which stipulates the LBC serves as the repository for the official certificates of incorporation and boundaries. Based on our longstanding and positive working relationship with the LBC staff, and the fact we were willing to take on the work load, the Commissioner of the then Community and Regional Affairs Department agreed to designate the Department of Labor as the agency to submit these legal boundary changes via the BAS.
The U.S. Census Bureau conducts the Boundary and Annexation Survey or BAS annually to collect information about legally defined geographic areas. The BAS is used to update information about the legal boundaries and names of all governmental units in the United States.
The Census Bureau uses the boundary information collected in the BAS to tabulate data for various censuses and surveys, such as the American Community Survey and other Census Bureau programs, such as the Population Estimates Program. Title 13, United States Code authorizes this voluntary survey. Up until 1998, the BAS was sent out to each city and borough in Alaska for their review.
During our work with the census bureau’s geographic programs in the early 1990’s, however, we discovered that the level of accuracy of the boundaries of all the State’s cities and boroughs in the census TIGER file varied too much, so we proposed an effort to consolidate the BAS work and funnel it through our office so we could ensure that the boundaries of each and every city were correctly represented. But the census bureau only recognized the Local Boundary Commission as the state level entity for providing that review, in lieu of each individual city, due to state statute which stipulates the LBC serves as the repository for the official certificates of incorporation and boundaries. Based on our longstanding and positive working relationship with the LBC staff, and the fact we were willing to take on the work load, the Commissioner of the then Community and Regional Affairs Department agreed to designate the Department of Labor as the agency to submit these legal boundary changes via the BAS.
17. 17 2010 Census – timeline of participant programs in Alaska The next BAS will start in January of next year and will include the opportunity to review the boundaries of every city regardless of size and all of the boroughs. Since we methodically corrected each of these places prior to census 2000, the bulk of the current BAS work will identifiy borough or city annexations and new borough creations. The next BAS will start in January of next year and will include the opportunity to review the boundaries of every city regardless of size and all of the boroughs. Since we methodically corrected each of these places prior to census 2000, the bulk of the current BAS work will identifiy borough or city annexations and new borough creations.
18. 18 2010 Census – timeline of participant programs in Alaska The participant statistical areas program enables local participants to delineate statistical areas for which census tabulations are created. These statistical areas are referred to as census block groups, census tracts, census designated places or CDPs and census sub areas. While the overall structure of this program has remained fairly consistent over the last few decades, there are typically changes to the criteria used to determine these areas for each new census. The participant statistical areas program enables local participants to delineate statistical areas for which census tabulations are created. These statistical areas are referred to as census block groups, census tracts, census designated places or CDPs and census sub areas. While the overall structure of this program has remained fairly consistent over the last few decades, there are typically changes to the criteria used to determine these areas for each new census.
19. 19 2010 Census – timeline of participant programs in Alaska As can be seen by the schedule above, this program began earlier this year with the criteria for each of the 4 statistical groups being published in the federal register Comments are currently being reviewed for the final criteria release in early 2008.
All borough governments, and our office for the State, will be invited to participate.
The review and redrawing of these statistical boundaries prior to the last 2 censuses, was one of our greatest tasks, because we are responsible for delineating the statistical boundaries within all the census areas which make up the entire unorganized borough.
These programs have also provided us great opportunities to establish good working relationships with all the boroughs, and many if not most of the cities and places in our State, as we typically provide both training about the program content as well as assist with reviewing the new delineations prior to submission to the census bureau. As can be seen by the schedule above, this program began earlier this year with the criteria for each of the 4 statistical groups being published in the federal register Comments are currently being reviewed for the final criteria release in early 2008.
All borough governments, and our office for the State, will be invited to participate.
The review and redrawing of these statistical boundaries prior to the last 2 censuses, was one of our greatest tasks, because we are responsible for delineating the statistical boundaries within all the census areas which make up the entire unorganized borough.
These programs have also provided us great opportunities to establish good working relationships with all the boroughs, and many if not most of the cities and places in our State, as we typically provide both training about the program content as well as assist with reviewing the new delineations prior to submission to the census bureau.
20. 20 2010 Census – timeline of participant programs in Alaska For those of you not familiar with these census statistical areas, the next few slides will show what they look like. Here, the green outlines depict census tracts within the Kenai Peninsula borough. Tracts are more or less based on a threshold of around 4000 persons. The next slide will focus on Tract 5For those of you not familiar with these census statistical areas, the next few slides will show what they look like. Here, the green outlines depict census tracts within the Kenai Peninsula borough. Tracts are more or less based on a threshold of around 4000 persons. The next slide will focus on Tract 5
21. 21 2010 Census – timeline of participant programs in Alaska Within Tract 5, shown in the green outline here, are 4 block groups, the light blue shaded areas outlined by a darker blue line. And finally the individual blocks which make up each block group are represented by the dark brown lines.
Within Tract 5, shown in the green outline here, are 4 block groups, the light blue shaded areas outlined by a darker blue line. And finally the individual blocks which make up each block group are represented by the dark brown lines.
22. 22 2010 Census – timeline of participant programs in Alaska Here is the same area as Tract 5, but instead Census Designated Places are being displayed. Census designated places (CDPs) are closely settled, and named, unincorporated communities that generally contain a mixture of residential, commercial, and retail areas similar to those found in incorporated places of similar sizes.
All 27 of the State’s census areas and boroughs statistical boundaries will be up for review next year.Here is the same area as Tract 5, but instead Census Designated Places are being displayed. Census designated places (CDPs) are closely settled, and named, unincorporated communities that generally contain a mixture of residential, commercial, and retail areas similar to those found in incorporated places of similar sizes.
All 27 of the State’s census areas and boroughs statistical boundaries will be up for review next year.
23. 23 2010 Census – timeline of participant programs in Alaska The last participant program I’ll talk about is the School District Review Program. The Census Bureau creates special tabulations of decennial census data by school district geography. These tabulations provide detailed demographic characteristics of the nation's public school systems and offer one of the largest single sources of children's demographic characteristics currently available. Information is distributed through the National Center for Education Statistics (NCES).
The last participant program I’ll talk about is the School District Review Program. The Census Bureau creates special tabulations of decennial census data by school district geography. These tabulations provide detailed demographic characteristics of the nation's public school systems and offer one of the largest single sources of children's demographic characteristics currently available. Information is distributed through the National Center for Education Statistics (NCES).
24. 24 2010 Census – timeline of participant programs in Alaska The School District Review Program, conducted every two years, is of vital importance for each state's allocation under Title I of the Elementary and Secondary Education Act as amended by the No Child Left Behind Act of 2001. The school district information obtained through this program, along with the Census 2000 population and income data, current population estimates, and tabulations of administrative records data, are used in forming the Census Bureau's estimates of the number of children aged 5 through 17 in low-income families for each school district. These estimates are the basis of the Title 1 allocation for each school district.
The school district review program, similar to the BAS, requests updates on school boundary changes, consolidations, dissolutions or name changes. The Department of Education has designated the Department of Labor as the state’s school district mapping coordinator. As most of you are aware, in most of the unorganized borough, outside of cities, Rural Education Attendance Areas replace city or borough school districts. The deadline for submission of school district or REAA boundary corrections is December of this year.
The School District Review Program, conducted every two years, is of vital importance for each state's allocation under Title I of the Elementary and Secondary Education Act as amended by the No Child Left Behind Act of 2001. The school district information obtained through this program, along with the Census 2000 population and income data, current population estimates, and tabulations of administrative records data, are used in forming the Census Bureau's estimates of the number of children aged 5 through 17 in low-income families for each school district. These estimates are the basis of the Title 1 allocation for each school district.
The school district review program, similar to the BAS, requests updates on school boundary changes, consolidations, dissolutions or name changes. The Department of Education has designated the Department of Labor as the state’s school district mapping coordinator. As most of you are aware, in most of the unorganized borough, outside of cities, Rural Education Attendance Areas replace city or borough school districts. The deadline for submission of school district or REAA boundary corrections is December of this year.
25. 25 REENGINEERING THE DECENNIAL CENSUS OVERVIEW Which brings us to the last and newest piece of the reengineered component…….The American Community Survey
The ACS is a nationwide monthly survey designed to provide reliable and timely demographic, housing, social, and economic data every year.
The ACS is replacing the 2010 Census long form by collecting detailed information throughout the decade. While the primary aim of the census is coverage — or
obtaining a complete population enumeration—the ACS program is focused on content—obtaining accurate information about population and housing characteristics.
There are so many different aspects of the ACS which demand attention and discussion, especially now that the data releases have begun. But today, if there is one thing I can impress upon you, it is to use the data with caution. It looks and seems to be very similar to the decennial census data everyone is familiar with. But there are differences and the more you can read and learn about the sampling and the accuracy of the data, the better equipped you will be to avoid making unsound decisions or judgements based on that data.
In the remaining time, I’d like to focus on the sampling size being used for questionnaire distribution since this will have some of the largest impacts on Alaska’s small area data.
Which brings us to the last and newest piece of the reengineered component…….The American Community Survey
The ACS is a nationwide monthly survey designed to provide reliable and timely demographic, housing, social, and economic data every year.
The ACS is replacing the 2010 Census long form by collecting detailed information throughout the decade. While the primary aim of the census is coverage — or
obtaining a complete population enumeration—the ACS program is focused on content—obtaining accurate information about population and housing characteristics.
There are so many different aspects of the ACS which demand attention and discussion, especially now that the data releases have begun. But today, if there is one thing I can impress upon you, it is to use the data with caution. It looks and seems to be very similar to the decennial census data everyone is familiar with. But there are differences and the more you can read and learn about the sampling and the accuracy of the data, the better equipped you will be to avoid making unsound decisions or judgements based on that data.
In the remaining time, I’d like to focus on the sampling size being used for questionnaire distribution since this will have some of the largest impacts on Alaska’s small area data.
26. 26 The American Community Survey The ACS is based on a smaller effective sample size than that of the census long form, about 12.5% vs 17%. The census bureau’s reasoning for this is that the moderate increase in sampling error which results from both a rolling sample and smaller sample is a reasonable trade-off in order to have annual updates. The cost of collecting sufficient data to match the census sample size was beyond the budget constraints surrounding the start up of the ACS.
This slide compares the sampling rates of different areas based on number of housing units, used in census 2000 to that which is being used in the ACS.
The smaller sample size continues to be a weakness of the ACS compared with the long-form sample resulting in significantly larger margins of error in the ACS estimates, even when cumulated over 5 years. Another reason is the greater variation in the ACS sample weights resulting from the subsampling for field interviewing of households not responding by mail or telephone. Also, the post censal population and housing estimates used as survey controls are less effective than the full census controls used with the long-form sample as they are subject to unmeasured estimation error, they are applied at a less detailed level than the census controls, and they are not directly related to the ACS in the way that the census controls are related to the long-form sample.
The ACS is based on a smaller effective sample size than that of the census long form, about 12.5% vs 17%. The census bureau’s reasoning for this is that the moderate increase in sampling error which results from both a rolling sample and smaller sample is a reasonable trade-off in order to have annual updates. The cost of collecting sufficient data to match the census sample size was beyond the budget constraints surrounding the start up of the ACS.
This slide compares the sampling rates of different areas based on number of housing units, used in census 2000 to that which is being used in the ACS.
The smaller sample size continues to be a weakness of the ACS compared with the long-form sample resulting in significantly larger margins of error in the ACS estimates, even when cumulated over 5 years. Another reason is the greater variation in the ACS sample weights resulting from the subsampling for field interviewing of households not responding by mail or telephone. Also, the post censal population and housing estimates used as survey controls are less effective than the full census controls used with the long-form sample as they are subject to unmeasured estimation error, they are applied at a less detailed level than the census controls, and they are not directly related to the ACS in the way that the census controls are related to the long-form sample.
27. 27 The American Community Survey Within Alaska the sample is further affected by a higher rate of unmailable and undeliverable questionnaires as well as a remote Alaska sampling operation.
The ACS employs 3 modes of data collection:
Mailout/Mailback
Computer Assisted Telephone Interviews or CATI and
Computer Assisted Personal Interviews or CAPI
The general timing of data collection is:
Month one Addresses determined to be mailable are sent a questionnaire via postal service
Month 2 All non responding addresses and undeliverable mail with phone numbers are sent to CATI
Month 3 A 2 In 3 sample of mail non responses without phone numbers, and CATI non responses and unmailable addresses are sent to CAPI
Here is problem in Alaska: Un-mailable rates are very high, about 29% of the initial sample in 2005 was classified as un-mailable making that 29% of the sample immediately reduced to 2/3rds since there is no CATI option for un-mailables and they go directly to CAPI. 12 census areas or boroughs had un-mailable rates above 50% and 7 of these were above 75%. The census bureau has not taken any steps to improve this issue to date, so the 2006 data and the 2007 data being collected now are all victims of this same problem.
In addition, undeliverable rates are also very high here. About 21%, and this number could be higher, of the initial sample was returned by the USPS as undeliverable. These cases are not oversampled for CAPI, so depending on the area, it could resampled at as low a rate as 1 in 3.
Finally, in remote Alaska, there are two additional differences from how the ACS is being conducted in the rest of the country. Here geographic areas are assigned to a shortened interview period of either January to April or September to December. A few areas with sufficient sample are split between the two. So 12 months of data collection are compressed into 4. In addition, since these are all onsite personal interviews, by definition, the initial sample is reduced by the sub sampling CAPI rate to 2 in 3.
Alaska is clearly losing sample, especially in the rural areas, enough so to bring into question the reliability of any of the data releases.Within Alaska the sample is further affected by a higher rate of unmailable and undeliverable questionnaires as well as a remote Alaska sampling operation.
The ACS employs 3 modes of data collection:
Mailout/Mailback
Computer Assisted Telephone Interviews or CATI and
Computer Assisted Personal Interviews or CAPI
The general timing of data collection is:
Month one Addresses determined to be mailable are sent a questionnaire via postal service
Month 2 All non responding addresses and undeliverable mail with phone numbers are sent to CATI
Month 3 A 2 In 3 sample of mail non responses without phone numbers, and CATI non responses and unmailable addresses are sent to CAPI
Here is problem in Alaska: Un-mailable rates are very high, about 29% of the initial sample in 2005 was classified as un-mailable making that 29% of the sample immediately reduced to 2/3rds since there is no CATI option for un-mailables and they go directly to CAPI. 12 census areas or boroughs had un-mailable rates above 50% and 7 of these were above 75%. The census bureau has not taken any steps to improve this issue to date, so the 2006 data and the 2007 data being collected now are all victims of this same problem.
In addition, undeliverable rates are also very high here. About 21%, and this number could be higher, of the initial sample was returned by the USPS as undeliverable. These cases are not oversampled for CAPI, so depending on the area, it could resampled at as low a rate as 1 in 3.
Finally, in remote Alaska, there are two additional differences from how the ACS is being conducted in the rest of the country. Here geographic areas are assigned to a shortened interview period of either January to April or September to December. A few areas with sufficient sample are split between the two. So 12 months of data collection are compressed into 4. In addition, since these are all onsite personal interviews, by definition, the initial sample is reduced by the sub sampling CAPI rate to 2 in 3.
Alaska is clearly losing sample, especially in the rural areas, enough so to bring into question the reliability of any of the data releases.
28. 28 American Community Survey: Data Products
29. 29 This slide shows the ACS data product release:
Here are some important things to note from this slide:
One-year period estimates will be released during the year after which the data were collected. For example, 2005 ACS data was released last year, and the 2006 ACS data was just released a few weeks ago.
One-year period estimates will be released every year for geographic areas with populations of 65,000 or more.
Three-year period estimates will be released every year for geographic areas of 20,000 or more. The first year when three-year period estimates will be released is 2008. Three-year period estimates will be released for geographic areas of 20,000 or more every year thereafter.
Five-year period estimates will be released every year for geographic areas of all population sizes. The first year when five-year period estimates will be released is 2010. Five-year period estimates will be released for geographic areas of all sizes every year thereafter.
For geographic areas with populations of 65,000 or more: one-year, three-year, and five-year data products will be released in 2010 and every year thereafter.This slide shows the ACS data product release:
Here are some important things to note from this slide:
One-year period estimates will be released during the year after which the data were collected. For example, 2005 ACS data was released last year, and the 2006 ACS data was just released a few weeks ago.
One-year period estimates will be released every year for geographic areas with populations of 65,000 or more.
Three-year period estimates will be released every year for geographic areas of 20,000 or more. The first year when three-year period estimates will be released is 2008. Three-year period estimates will be released for geographic areas of 20,000 or more every year thereafter.
Five-year period estimates will be released every year for geographic areas of all population sizes. The first year when five-year period estimates will be released is 2010. Five-year period estimates will be released for geographic areas of all sizes every year thereafter.
For geographic areas with populations of 65,000 or more: one-year, three-year, and five-year data products will be released in 2010 and every year thereafter.
30. ACS Data for Counties: Alaska Counties by Size 30 This slide shows the volume of geography which falls into the less than 20,000 persons category. And this is only showing the first level sub state areas. Impacts are no data until at least 2010, tabulations based on 5 years of averaged data, and the reduced sample size which brings into question the validity or reliability of the ACS data.This slide shows the volume of geography which falls into the less than 20,000 persons category. And this is only showing the first level sub state areas. Impacts are no data until at least 2010, tabulations based on 5 years of averaged data, and the reduced sample size which brings into question the validity or reliability of the ACS data.
31. 31
