It is based on landline and cellular telephone interviews with a nationally representative random sample of 1,735 adults age 40 or older. Interviews included 1,130 respondents on landline telephones and 605 on cellphones.
Digits in the phone numbers dialed were generated randomly to reach households with unlisted and listed landline and cellphone numbers.
Interviews were conducted in both English and Spanish.
As is done routinely in surveys, results were weighted, or adjusted, to ensure that responses accurately reflect the population's makeup by factors such as age, sex, education, race and landline or cellphone use.
No more than 1 time in 20 should chance variations in the sample cause the results to vary by more than plus or minus 3.2 percentage points from the answers that would be obtained if all adults in the U.S. were polled.
There are other sources of potential error in polls, including the wording and order of questions.
The questions and results are available at http://www.longtermcarepoll.org