This section will contain information relevant to the Current Population Survey, December 1994: Lead Paint Survey file that becomes available after the file is released. The cover letter to the updated information should be filed behind this page.
User notes will be sent to all users who purchased their file or technical documentation from the Census Bureau.
(April 1994 - August 1995)
ESTIMATES FOR METROPOLITAN AND NONMETROPOLITAN AREAS
During the period April 1994 through June 1995, the Bureau of the Census is systematically introducing a new sample design for the Current Population Survey (CPS) based on the results of the 1990 Decennial Census. During this phase-in period, CPS estimates are being made from two distinct sample designs; i.e., the old 1980 sample design and the new 1990 sample design. While most CPS estimates are thought to be minimally affected by this mixed sample, metropolitan/nonmetropolitan estimates and related CPS geographic estimates are subject to greater error and variability. The causes of these errors are differences in the metropolitan area definitions used in each design, differences in coverage, errors in geographic recoding, and changes in CPS sample areas (including redefining sample areas to correspond to the updated metropolitan definitions.)
Using the results from each Decennial Census, the Office of Management and Budget (OMB) revises its official definitions for metropolitan areas. This usually involves adding counties or groups of counties to existing metropolitan areas or designating new metropolitan areas based on certain criteria. As a result, each new CPS sample design represents a larger metropolitan population than its predecessor. The 1980 sample design is based on projected metropolitan area definitions as of June 30, 1983; the 1990 design uses anticipated definitions as of June 30, 1993. During this period, the total number of metropolitan areas increased from 318 to 323. This situation is exacerbated since the mix of the designs (that is, the percent of each design in sample) changes during the phase-in period as more new-design households are introduced. For CPS microdata files containing data collected during the period April 1994 through May 1995, the 1990 design sample was recoded to reflect 1983 metropolitan area definitions. Despite efforts to make the data from the two sample designs consistent, the net result of the different metropolitan definitions in combination with the other changes mentioned above is increased error in metropolitan, nonmetropolitan and related estimates during this phase-in period. As an example, estimates from the January 1995 CPS show an increase of only 1 percent in total civilian noninstitutional population aged 16 and over for metropolitan areas between the 1980 and 1990 designs, but the estimated central city population for the 1990 design is 6 percent higher for the 1990 design. Therefore, the Bureau recommends that users exercise extreme caution when analyzing any tabulations or comparisons using these or related variables during this period.
Another constraint on the use of geographic data from this time period is that not all geographic codes on the CPS file were recoded to reflect both the 1980 and 1990 metropolitan definitions. Given below are two lists of variables on the Pre-April 1994 public use files. The first list shows which variables were recoded and are on the files. The second lists contains the variables that have been removed from the files.
April 94-May 95
Non-March Files March 1995
Variable Location Location
RECODED VARIABLES
MSA/PMSA FIPS CODE CHARACTERS 97-100 CHARACTERS 44-47
MSA STATUS CODE CHARACTERS 112-113 CHARACTER 57
CENTRAL CITY STATUS CODE CHARACTERS 108-109 CHARACTER 58
INDIVIDUAL CENTRAL CITY CODE CHARACTERS 110-111 CHARACTER 285
VARIABLES DELETED
STATE RANK CHARACTERS 95-96 CHARACTERS 42-43
PMSA RANK N/A CHARACTERS 48-49
MSA/CMSA RANK CHARACTERS 101-103 CHARACTERS 50-52
MSA SIZE CHARACTERS 104-105 CHARACTER 55
CMSA FIPS CODE CHARACTERS 106-107 CHARACTERS 53-54
MSA/PMSA SIZE N/A CHARACTER 56
With the exception of the metropolitan size classifier, all previous
breakouts of specific metropolitan tallies can be produced with the
data appearing on the April 1994-May 1995 files.
MATCHING OF HOUSEHOLDS DURING THIS REDESIGN PERIOD
As was the case with previous redesigns of CPS, we will be revising the
geographic identifiers on the CPS public use files to incorporate the
new sample and utilize the updated (June 30, 1993) metropolitan area
definitions. We plan to introduce these new definitions on the
September 1995 public use file. During this changeover, however, we
must take steps to prevent the matching of households containing
different sets of detailed geography. We do this in accordance with
Title 13, United State Code, to protect the confidentiality of our
respondents. Specifically, we will revise our household identification
numbering scheme to preclude matching across time frames with different
sets of geographic variables.
This changeover, along with revisions to the internal census household
numbering scheme, have revised the methodology for some matching of
households across CPS public use files. In general, this follows the
pattern of ten years ago in that data for the three separate time
frames are only matchable (within the constraints of the CPS rotation
pattern) to itself. These time frames are:
1. Data collected in or prior to May 1995.
2. Data collected in June, July, or August of 1995.
3. Data collected in or after September 1995.
Given below are procedures for matching households using data collected
in 1994 or 1995:
1993 to 1994:
Continue using the 12-digit household identification number as
before.
January 1994 through May 1995:*
Use either the FIPS or Census State Code in combination with the
12-digit household ID number and the serial suffix.
June 1995 through August 1995:*
Use the household ID number in combination with state and serial
suffix for household matching. Also note that during this three
month period, there will be no substate geographic identifiers
carried on the CPS public use files.
September 1995 Files Forward:
Use the household ID number to match households.
If you have any questions regarding the changeover to the new
geographic identifiers and matching of households, call Greg
Weyland on (301) 457-3806. See the May 1994 issue of the Bureau
of Labor Statistics' issue of Employment and Earnings or call
Donna Kostanich on (301) 457-4275 for further information
regarding CPS sample redesign.
*You will also need the use of these three fields if you want to
place the file in a household sort or group household records
together.
May 1997
