You have reached your limit of free articles this month.

Enjoy unlimited access to myAJC.com

Starting at just 99¢ for 8 weeks.

GREAT REASONS TO SUBSCRIBE TODAY!

  • IN-DEPTH REPORTING
  • INTERACTIVE STORYTELLING
  • NEW TOPICS & COVERAGE
  • ePAPER
X

You have read of premium articles.

Get unlimited access to all of our breaking news, in-depth coverage and bonus content- exclusively for subscribers. Starting at just 99¢ for 8 weeks

X

Welcome to myAJC.com

This subscriber-only site gives you exclusive access to breaking news, in-depth coverage, exclusive interactives and bonus content.

You can read free articles of your choice a month that are only available on myAJC.com.

AJC January 2017 poll methodology statement


Abt SRBI conducted the survey of Georgia residents, 18 years and older, on behalf of the Atlanta Journal Constitution. The survey included telephone interviews with a representative sample of 1,092 Georgia residents (including 919 registered voters). Telephone interviews were conducted by landline (n=396) and cell phone (n=696). Interviewing was conducted from January 2nd to January 5th, 2017. 

 

Sampling 

The sample design was a multiple frame sample using a list Georgia registered voters (RV) with their cell phone or landline numbers appended and a random digit dialed (RDD) frame of cell phone numbers and landline numbers with a Georgia telephone exchange. This sample design is referred to as a “multiple-frame” because it includes four different frames: the RDD landline frame, the RDD cellphone frame, the RV cellphone frame and the RV landline frame. 

 

The RV frame contains some information that people who register to vote in Georgia is asked to provide, including their landline or cellphone number. About 75% of the registered voters in Georgia provide either their landline or cellphone number. For this reason, the RDD landline and cellular frames were also used to supplement the sample in order to address a potential coverage problem on the RV frame. 

 

The RDD landline frame is constructed by compiling all Georgia telephone exchanges that are classified as providing regular telephone service. The frame is referred to as “list-assisted” because a complete file of directory-listed residential numbers is used to remove 100-banks from the frame if they contain zero residential listings. The remaining 100-banks are “working” and used to enumerate all the telephone numbers within the bank from which a sample is drawn. All landline numbers (directory-listed and unlisted) in the working banks are eligible to be randomly dialed. Telephone numbers known to belong to businesses are removed. 

The RDD cellular telephone frame begins with 1,000-blocks constructed from exchanges that provide cellular telephone service. The frame of 1,000-blocks is then expanded to the 100-block level to identify and remove “mixed use” 100-blocks, or those that include landline numbers. The result is a sampling of cellular 100-blocks that is mutually exclusive of the list-assisted RDD sampling frame described above. 

 

First, a random sample of landline numbers was drawn from the RDD frame. Then, our RV frame vendor flagged in our RDD sample the landline numbers that were also present in the RV frame and a random sample of landline numbers was drawn from the RV list excluding the matched numbers. This way, a single landline number is selected from each of the two frames. The same process was applied to the cellular samples. 

 

For the landline samples, interviewers were asked to speak with the youngest adult male or female currently at home based on a random rotation. If no male/female was available, interviewers asked to speak with the youngest adult of the other gender. For the cell samples, interviews were conducted with the person who answered the phone. Interviewers verified that the person was an adult and in a safe place before administering the survey. 

Weighting 

The final weights produced for this survey accounted for the multiple frame sample design and aligned the sample to match the population parameters of the adult population in Georgia. To construct the weights, we used the full sample of 1,092 Georgia residents. The full sample was post-stratified (raked) to benchmark demographic distributions for the Georgia adult population, as described below. The benefit of this approach is that statewide benchmarks for all adults are available from the Census Bureau and highly accurate and reliable. 

The first stage of weighting corrected for different probabilities of selection associated with the number of adults in the household and the respondent’s telephone usage (landline only, cell phone only or has both kinds of phones). This weighting also adjusts for the overlapping landline and cell sample from both the RV and RDD frames and the relative sizes of each frame and each sample. 

The second stage of weighting balanced sample demographics to estimated adult population parameters for the state of Georgia. The sample was balanced to match adult population parameters for sex, age, education level, race/Hispanic ethnicity, region (North, Atlanta Metro, Atlanta Exurbs, Southeast, Southwest), and telephone usage (cell-only, dual-user, landline-only). The demographic population parameters were computed from the 2015 American Community Survey (ACS). The population parameter for region of state was obtained from the 2015 Census Population Estimates. The telephone usage population estimates for Georgia were constructed from model-based state-level estimates released by the National Center for Health Statistics for the year 2015 . 

The second-stage weighting was conducted using an operation known as raking ratio estimation, or “raking”. Raking is used to reduce the risk of biases due to nonresponse and non-coverage in sample surveys. The raking procedure uses an iterative technique that simultaneously calibrates the sample to population distributions defined by socio-demographic parameters. After the raked weights were generated, we examined the distribution of values. The final weights were trimmed at the 2.5 and 97.5 percentiles to prevent individual interviews from having too much influence on the final results. 

Margin of Error 

The margin of error for an estimate is a measure of uncertainty that reflects the fact that the estimate is derived from a sample drawn from the population. If one were to draw a second sample in the exact same manner, the estimate would be different from the first simply due to the fact that the sample contains different members of the population. A third sample would be different from the first two, and so on. The margin of error measures how different estimates could be based on drawing different samples from the same population. 

 

The error margin for the entire sample of 1,092 residents is +/-3.69 percentage points. For the sample of 919 registered voters, the margin or error is +/-4.04 percentage points. This includes a “design effect” of 1.55 for the general population sample and 1.56 for the registered voter sub-sample. The design effect is the amount of variability introduced by the sample design, such as the dual-frame sample and weighting.


Reader Comments ...


Next Up in Georgia Politics

Studies: despair plays part in undiagnosed breast cancer in Georgia
Studies: despair plays part in undiagnosed breast cancer in Georgia

A pair of new studies on breast cancer from Georgia State University point to a surprising medical villain: economic despair. Both of the GSU studies looked at breast cancer that goes undiagnosed for too long. One of the studies by the university’s School of Public Health, on a type of the disease called inflammatory breast cancer, found a cluster...
Study: Atlanta hospital most vulnerable to Medicaid cuts

If the Obamacare revision the U.S. House of Representatives passed in May became law, the Georgia hospital to lose the most Medicaid funding would be Children’s Healthcare of Atlanta at Hughes Spalding, according to a new analysis by the Georgia Budget and Policy Institute. The U.S. Senate is expected to release its own version of the healthcare...
Watchdog: What does the Civil War have to do with us?
Watchdog: What does the Civil War have to do with us?

When House Speaker David Ralston punished fellow Republican Rep. Tommy Benton last week, stripping him of his committee chairmanship and removing him from a study committee on civics education, it came after nearly two years of provocative political acts. But it was the distribution to his House colleagues of an article from the magazine...
While losing, Ossoff easily won DeKalb’s vote in 6th District
While losing, Ossoff easily won DeKalb’s vote in 6th District

Democrat John Ossoff lost the 6th District race Tuesday, despite easily carrying DeKalb County’s portion of the vote. He recorded 33,847 votes to Republican Karen Handel’s 24,070 in the faithfully blue county, according to unofficial results. Handel prevailed in the northernmost eight precincts in the district, which also includes...
How did your Cobb neighbors vote in the 6th District runoff election?
How did your Cobb neighbors vote in the 6th District runoff election?

Republican Karen Handel beat Democrat Jon Ossoff in the 6th Congressional District race Tuesday night, becoming Georgia’s first female Republican member of the U.S. House. What would usually be a tame special election in an historically red section of the Atlanta suburbs brought obscene amounts of national attention and dollars...
More Stories