05/19/2014 04:07 EDT | Updated 07/18/2014 05:59 EDT

How the AP-NORC Center for Public Affairs poll on long-term care was conducted

The Associated Press-NORC Center for Public Affairs Research survey on long-term care was conducted from March 13 to April 23 by NORC at the University of Chicago. It is based on landline and cellular telephone interviews with a nationally representative random sample of 1,419 adults age 40 or older. Interviews included 1,014 respondents on landline telephones and 405 on cellular phones.

Digits in the phone numbers dialed were generated randomly to reach households with unlisted and listed landline and cellphone numbers.

Interviews were conducted in 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, region and race. In addition, the weighting took into account patterns of phone use — landline only, cellphone only and both.

No more than 1 time in 20 should chance variations in the sample cause the results to vary by more than plus or minus 3.6 percentage points from the answers that would be obtained if all adults age 40 or older in the U.S. were polled.

The survey was conducted with funding from The SCAN Foundation.

There are other sources of potential error in polls, including the wording and order of questions.

The questions and results are available at .