[CTPP] Differences when comparing short form to long form data

-----Original Message----- From: Wu, Sen-Yuan [mailto:Sywu@DOL.STATE.NJ.US] Sent: Tuesday, July 30, 2002 7:02 AM To: FSCPE(a)LISTSERV.LOUISVILLE.EDU Subject: Re: Demographic Profile Errors In New Jersey, most discrepancies between SF1 and SF3 were found in CDPs. The differences between the 100% and sample population counts were as high as 38.1% in Diamond Beach CDP (218 vs. 135) and 31.4% in Vista Center CDP (541 vs. 711). Other than the CDPs, only 7 (out of 566) municipalities had 5% or more differences in population or housing unit counts. Pine Valley Borough had the largest discrepancies (20% in population, 66.7% in housing units). All except one are tiny municipalities with less than 600 residents. Sen-Yuan Wu New Jersey Department of Labor Division of Labor Market & Demographic Research Tel. 609-292-0077, Fax 609-984-6833 <http://www.state.nj.us/labor/lra>

There appear to be some problems with this. We ran a test with our DP datasets, comparing the 100% and sample counts for all places. The summary report can be viewed at http://mcdc2.missouri.edu/pub/data/sf3prof/check_totpops.pdf . The biggest problem, in terms of pct difference in the counts, is definitely in the very small places. There are 593 places in the country where the difference was 25% or more and 566 of these were for places with 500 people or less. The report also includes a listing of these 593 places, sorted by state and descending Pct Difference. The winner of the worst sample estimate award is Blacksville CDP, Ga. They had a 100% count of 4 people, but the sample estimate was 52. John Blodgett OSEDA - Office of Social & Economic Data Analysis U. of Missouri Outreach and Extension 626 Clark Hall - UMC Columbia, MO 65211 (573) 884-2727 blodgettj(a)umsystem.edu URL: http://oseda.missouri.edu/jgb/ -----Original Message----- From: jeff hardcastle [mailto:jhardcas@UNR.EDU] Sent: Friday, July 26, 2002 11:30 AM To: FSCPE(a)LISTSERV.LOUISVILLE.EDU Subject: Demographic Profile Errors I am not sure if this has happened to states for the Demographic Profiles that include SF1 and SF3 data but in Nevada's case there are serious problems that suggest that the whole set of profiles needs to be reviewed for errors. These errors appear to be more than standard sampling and response errors. During a quick review counties look better than places however it appears that there may be geocoding errores in the sample data. There also appears to be differences in what the sample data is weighted against. The place that brought this to my attention was Searchlight NV where tge DP-1 pop is 576 and the housing unit count is 444. On DP-2 through 4 the pop is 768 and the unit count is 595. A 33% and a 34% difference respectively. The way I tumbled to this was that a reporter had seen that Searchlight had no native Nevadans living there. He went to Searchlight and interviewed people and found that most of them if not all were natives. (Searchlight is an old mining down south of Las Vegas and in the middle of very open country.) Is this kind of error being found elsewhere? -- peace, Jeff Hardcastle (775) 784-6353 Phone (775) 784-4337 Fax jhardcas(a)unr.edu e-mail "shifts happen" http://publicconversations.org/