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Coming Soon from the American Community Survey
On or about the 9th of December, the Census Bureau plans to release the first set of period estimates based on American Community Survey data collected over the 3-year period 2005 to 2007. This will be a landmark event in the evolution of the
ACS - the first time the Census Bureau has released such multi-year estimates since the full survey went into effect in 2005.
This means that data will now be available for geographic areas with a minimum population of 20,000 (per the most recent official Bureau estimates.) Up to now we have seen data only for areas of at least 65,000. In Missouri, this means that we should be getting detailed social and economic 3-year period estimates for the following entities:
- Cities: Arnold, Ballwin, Belton, Blue Springs, Cape Girardeau, Chesterfield, Ferguson, Florissant, Gladstone, Grandview, Hazelwood, Jefferson City, Joplin, Kirkwood, Liberty, Maryland Heights, Raytown, St. Charles, St. Peters, Sedalia, University City,
Webster Groves, Wentzville, and Wildwood .
- Counties: Adair, Audrain, Barry, Butler, Callaway, Camden, Clinton, Crawford, Dunklin, Henry, Howell, Johnson, Laclede, Lafayette, Lawrence, Lincoln, McDonald, Marion, Miller, Morgan, Newton, Nodaway, Pettis, Phelps, Polk, Pulaski, Randolph, Ray, St. Francois, Saline,
Scott, Stoddard, Stone, Taney, Texas, Vernon, Warren, Washington, and Webster
There will also be new data for the larger cities and counties (those over 65,000). Of course these data will differ from what we
have already seen with the single-year estimates. These new 3-year period estimates (what some users will want to call "moving averages", although the Bureau discourages use of that terminology for technical reasons) will be based on a much larger sample. As such, they should have significantly smaller sampling errors. That's the good news. The not-so-good thing is that they will be based on surveys taken anywhere from 1 to 4 years ago, so that the data will not be as current as the single-year figures. This is a new choice with which data users (and data providers such as the MCDC) shall need to start dealing. Our guess for now is that the 3-year period estimates are going to become the default figures that will see the most widespread use.
The Missouri Census Data Center is currently adapting our software to work with the new data. We are adding "period" parameter choices to our interactive applications so that users will be able to choose whether they want to see the single-year or three-year period estimates (for areas where there is a choice)
New Compass ACS Handbooks Available
The Census Bureau has been working on a series of introductory manuals for understanding and using the American Community Survey data, each one geared to a
specific audience and/or application. The first two compass modules were released in October and have been copied to the MCDC web site (in the /pub/data/acs/Docs subdirectory). These are rather large (60 to 70 page) PDF files that are intended to be read rather than used just as reference tools. One is intended for the general user and the other for the "business community".
The MCDC is planning to do workshops in March that will be based more or less on the material covered in these handbooks.
MCDC Enhancements to ACS2007 Base Tables Processing
In addition to working to get ready for the new data being released in December the MCDC has been working on making the data we already have
more readily accessible from our web site. We have particularly focused on a new methodology for downloading and converting the huge detailed "base" table collections from the Census Bureau. The results of our efforts can be viewed by Uexplore/Dexter users in the new basetbls subdirectory of the acs2007 main data directory. Users will note the existence of a Datasets.html file within this directory, which means we provide better access to the data sets within this directory, complete with detailed metadata modules. We have modified the software so that the Dexter modules recognize this collection as being table-based so that the selection menus in Part III of the Dexter query form let the user choose from tables instead of variables. We have also created a new Varlabs subdirectory of the new basetbls directory, which contains a set of 6 variable-level data dictionary files in plain text format that load quickly and are easy to search for keywords.
New ACS Base Tables Display Module Under Development
The MCDC has begun work on a new software module, called acstabgen, that will do for ACS data what our sf3tabgen module did for the very popular Summary File 3 data from the 2000 census. You may not recognize the name of this module, but if you have ever used the MCDC's 2k census standard demographic profile reports ("dp3_2k"), then you may have taken advantage of the ability to "drill down" to a detailed table that was the source of the variables extracted for the profile. We hope to do something very similar with the ACS profiles, allowing users to drill down to a more detailed "parent" table.
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