Sunday, August 3, 2008; 12:01 AM

This survey is part of an ongoing partnership of The Washington Post, the Henry J. Kaiser Family Foundation and Harvard University. The partners together developed and analyzed the survey. Each organization bears sole responsibility for the work that appears under its name. The Post and the Kaiser Family Foundation ¿ a nonprofit that researches health care and other issues ¿ paid for the survey.

The poll was conducted by telephone June 18 to July 7, among 1,350 randomly selected low-wage workers nationwide. Low-wage workers were defined as adults ages 18 to 64 working 30 or more hours a week, not self-employed and earned no more than $27,000 in 2007. This income threshold roughly corresponds with the bottom 40 percent of the country's workforce in terms of wages.

Interviews were conducted in English or Spanish and on traditional landline telephones or cell phones. The margin of sampling error for the full poll is plus or minus four percentage points. Error margins are larger for subgroups. Abt SRBI Inc. carried out the fieldwork.

As part of this project, we also conducted a series of wide-ranging, in-depth focus groups with low-wage workers in Philadelphia.

The project team from the foundation included Drew E. Altman, KFF president; Mollyann Brodie, KFF vice president for public opinion research; Claudia Deane and Elizabeth Hamel, KFF associate directors of public opinion research; and from Harvard, Robert J. Blendon, professor at the School of Public Health and John F. Kennedy School of Government; and John Benson, managing director of the Harvard Opinion Research Program.

© 2008 The Washington Post Company