Elon University Poll: Majority of N.C. residents oppose constitutional ban on same-sex marriage

From Elon University’s website:
Fifty-six percent of North Carolinians oppose a state constitutional ban on same-sex marriage, according to the latest Elon University poll, and the number of people who would prefer to see no legal recognition for same-sex couples has dropped since pollsters asked the same question two years ago.

The poll, conducted Sept. 25-29, 2011, surveyed 594 North Carolina residents and has a margin of error of plus or minus 4.02 percentage points. The sample is of the population in general, with numbers that include both landlines and cellular phones. The Elon University Poll does not restrict respondents by voter eligibility or likelihood of voting.

N.C. constitutional amendment banning same-sex marriage
September 2011: 56 percent oppose / 39 percent support
February 2011: 56 percent oppose / 38 percent support
March 2009: 50 percent oppose / 43 percent support

Oppose any legal recognition for same-sex couples:
September 2011: 34 percent
February 2011: 35 percent
March 2009: 44 percent

Support civil unions or partnerships, but not full marriage rights:
September 2011: 29 percent
February 2011: 29 percent
March 2009: 28 percent

Support full marriage rights:
September 2011: 33 percent
February 2011: 28 percent
March 2009: 21 percent

I. Survey Methodology
The Elon University Poll is conducted using a stratified random sample of households with telephones and wireless telephone numbers in the population of interest – in this case, citizens in North Carolina. The sample of telephone numbers for the survey is obtained from Survey Sampling International, LLC. Methodological information is also available at: http://www.elon.edu/e-web/elonpoll/methodology.xhtml.

Selection of Households
To equalize the probability of telephone selection, sample telephone numbers are systematically stratified according to subpopulation strata (e.g., a zip code, a county, a state, etc.), which yields a sample from telephone exchanges in proportion to each exchange’s share of telephone households in the population of interest. Estimates of telephone households in the population of interest are generally obtained from several databases. Samples of household telephone numbers are distributed across all eligible blocks of numbers in proportion to the density of listed households assigned in the population of interest according to a specified subpopulation stratum. Upon determining the projected (or preferred) sample size, a sampling interval is calculated by summing the number of listed residential numbers in each eligible block within the population of interest and dividing that sum by the number of sampling points assigned to the population.

From a random start between zero and the sampling interval, blocks are systematically selected in proportion to the density of listed household “working blocks.” A block (also known as a bank) is a set of contiguous numbers identified by the first two digits of the last four digits of a telephone number. A working block contains three or more working telephone numbers.

Exchanges are assigned to a population on the basis of all eligible blocks in proportion to the density of working telephone households. Once each population’s proportion of telephone households is determined, then a sampling interval, based on that proportion, is calculated and specific exchanges and numbers are randomly selected.

The methodology for the wireless component of this study starts with the determining which area code-exchange combinations in North Carolina are included in the wireless or shared Telcordia types. Similar to the process for selecting household telephone numbers, wireless numbers involve a multistep process in which blocks of numbers are determined for each area code-exchange combination in the Telcordia types.

From a random start within the first sampling interval, a systematic nth selection of each block of numbers is performed and a two-digit random number between 00 and 99 is appended to each selected nth block stem. The intent is to provide a stratification that will yield a sample that is representative both geographically and by large and small carrier. From these, a random sample is generated. Because exchanges and numbers are randomly selected by the computer, unlisted as well as listed household telephone numbers are included in the sample. Thus, the sample of telephone numbers generated for the population of interest constitutes a random sample of telephone households and wireless numbers of the population.