(continued from Indicators & Data)
Annual Data and Sources
As these data are drawn from sample surveys, they are estimates. Each estimate is accompanied by the upper and lower bounds of a 90 percent confidence interval; statistical analysis indicates there is a 90 percent chance the "true" number (the one that would be calculated if information were available on the entire population) lies within this confidence interval. The estimate sits at the midpoint of the confidence interval. (The width of the confidence interval is determined by the standard error, which also is provided in the spreadsheets.)
For less populated states (which have a small sample size), the confidence intervals can be quite wide. Consequently, users are encouraged to analyze the point estimates with care. When writing, in some cases they may want to refer to the upper and lower bounds of the confidence interval.
The ACS, annually published by the U.S. Census Bureau, provides a detailed socioeconomic and demographic profile of the U.S. population. The ACS is replacing the “long form” of the Decennial Census; the advantage of the ACS is annual collection, compared to collection once every ten years through the Decennial Census. Since 2000, the ACS is conducted nationwide with an annual sample of 3 million households. The 2007 the WPFP uses the Census 2005 ACS, the latest available.
The CPS is carried out by the Bureau of the Census on behalf of the Bureau of Labor Statistics (BLS). The Working Poor Families Project uses three components of the CPS. The CPS Basic Monthly Survey asks questions of over 60,000 households about employment status. The Annual Social and Economic Supplement (conducted every March) goes into some detail regarding income and work experience. Every two years, the Contingent Work Supplement asks questions regarding the temporary or permanent nature of employment. To the extent possible, the 2007 WPFP uses 2006 CPS data. For some measures, achieving statistical significance requires using a three-year average (2004-2006). The latest available data for contingent workers is 2005.
The Occupational Employment Statistics (OES) program of BLS surveys approximately 400,000 establishments per year, and produces state employment and median wage estimates for over 700 occupations.
Below are data files for each year of the WPFP.
WPFP 2006
- Conditions of Low-Income Working Families (xls)
- Education and Skills Status of Adults (xls)
- Economic Conditions in the States (xls)
- Conditions of Employment (xls)
- Supplemental Data (xls)
WPFP 2005
- American Community Survey (ACS) - 2003
- Current Population Survey (CPS) - 2004
- Occupational Employment Survey (OES) - 2003
WPFP 2004
- American Community Survey (ACS) - 2002
- Current Population Survey (CPS) - 2003
- Occupational Employment Survey (OES) - 2002
WPFP 2003
- American Community Survey (ACS) - 2001
- Current Population Survey (CPS) - 2002
- Occupational Employment Survey (OES) - 2001
