The Pew Research Center survey on the experiences of lesbian, gay, bisexual and transgender people was conducted April 11-29, 2013. The results are based on online interviews of 1,197 adults who self-identify as lesbian, gay, bisexual or transgender.
The nationwide survey was conducted online by the GfK Group of Palo Alto, Calif.
The original sample was drawn from a panel of respondents GfK recruited via phone or mail survey methods. The company provides Web access to panel recruits who don't already have it. With a probability basis and coverage of people who otherwise couldn't access the Internet, GfK's online surveys using KnowledgePanel are nationally representative.
The poll included interviews with 398 gay men, 277 lesbian women, 479 people who are bisexual and 43 people who identify primarily as transgender. The survey assessed sexual orientation and gender identity separately, and respondents indicated which group they felt best described them.
Results for the poll were weighted, or adjusted, to reflect the best estimates of demographics including gender, race, ethnicity, education, age and household income, as well as region and metropolitan area, for the LGBT population. The panel from which the survey respondents were selected is also weighted to reflect the adult population by demographic factors such as age, sex, race, education, income and homeownership status along with region, metropolitan area and Internet access.
No more than one time in 20 should chance variations in the sample cause the results to vary by more than plus or minus 4.1 percentage points from the answers that would be obtained if all self-identified lesbian, gay, bisexual or transgender 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://pewresearch.org/LGBT.