Early this week, we told you of a SurveyUSA poll, commissioned by 11Alive, that placed Georgia's races for governor and U.S. Senate in terms that mimicked past post-2002 cycles.

In the race for governor:

-- Republican incumbent Nathan Deal, 48 percent;

-- Democrat Jason Carter, 39 percent;

-- and Libertarian Andrew Hunt, 4 percent.

In the U.S. Senate contest:

-- Republican David Perdue, 48 percent;

-- Democrat Michelle Nunn, 41 percent;

-- and Libertarian Amanda Swafford, 3 percent.

But now we have a Landmark Communications survey, commissioned by Channel 2 Action News, released only four days later, that essentially flips those results. But the survey tracks closely with a previous WSB/Landmark poll from July. Check out the crosstabs here.

In the governor’s race, according to Landmark:

-- Carter, 44 percent;

-- Deal, 40 percent;

-- and Hunt, 4 percent;

In the race for U.S. Senate:

-- Nunn, 47 percent;

-- Perdue, 40 percent;

-- and Swafford, 3 percent.

Margin of error is roughly the same in both surveys – +/- 4.2 and 4 percent, respectively. But there are significant methodological differences between the two polls. The SurveyUSA poll was a combination of automated calls to land lines, and an Internet questionnaire conducted via smart phones or other devices.

Updated at 10 p.m. Sunday: We originally reported that Landmark Communications conducted live interviews via landlines. Mark Rountree, head of Landmark Communications, sent us this note on Sunday:

"I do want to clear up one item: our (Landmark) poll was a hybrid of IVR (recorded) and live calling, not just live calling. We dialed using live interviewers to cell phones, while IVR was used for landlines"

There are also some significant weighting differences. The SurveyUSA survey presumed a November turnout in which men make up a majority of voters, and placed African-American turnout at 26 percent.

The Landmark poll places black turnout at 29 percent, more in line with the historical trend. It also presumes a majority of female voters.

Below is the memo that Landmark’s Mark Rountree sent us:

#1. GOVERNOR — Democrat Senator Jason Carter continues to lead Republican Governor Nathan Deal, though the margin is shrinking. Today Carter leads Deal by a margin of 44-40%, with Libertarian Andrew Hunt carrying 4% of the vote.

However, Carter's lead has shrunk from an eight (+8) percentage-point lead on July 15 (49% to 41%) down to a lead of just four percent (+4) today.

GENDER DIFFERENCES: Sen. Carter carries 50% of female voters but only 38% of male voters, while Governor Deal wins 47% of men but only 34% of women voters.

REGIONAL DIFFERENCES: Governor Deal leads 42-40% outside of Metro Atlanta, while Sen. Carter leads in Metro Atlanta by 51-37%.

AGE DIFFERENCES: Governor Deal leads among younger voters and older voters, while Sen. Carter leads among voters who are in the 40-64 age range. Deal carries the 18-39 age range by a 45-35% margin and the 65%+ age group by 46-40%. However, Carter leads among voters in the 40-64 age range by a 50-36% margin.

#2. U.S. SENATOR— Democrat Michelle Nunn continues to lead Republican David Perdue in the Georgia U.S. Senate race. Nunn leads Perdue 47% to 40%, with 3% of voters voting for Libertarian candidate Amanda Swafford.

Men support Perdue by a 47-41% margin (+6), while women give Nunn an 18 percent lead (+18), 52-34%.

#3. POSSIBILITY CONTINUES TO INCREASE FOR RUNOFF ELECTIONS: This is the third poll conducted by Landmark Communications within a month concluding that no candidate for either Georgia Governor or U.S. Senator has reached 50% or more of the vote.

U.S. Senator Saxby Chambliss was thrown into a runoff election in 2008, though the incumbent ultimately prevailed and returned to the Senate. Republican State Senator Paul Coverdell pulled Democratic Senator Wyche Fowler in to a runoff election in 1992, with Coverdell ultimately winning the office in that runoff.

While it is too early to conclude that there will be a runoff election for Governor or for U.S. Senate, there is clear and recent precedence for these elections. Each passing week in which no candidate has crossed the 50%+1 mark brings the increased possibility of a runoff election for each office.

#4. PRESIDENT OBAMA'S HANDLING OF IRAQ SITUATION When voters were asked whether they approve or disapprove of the way President Barack Obama is handling the situation in Iraq, Georgians expressed disapproval by a 45-39% margin (-6%).

There is a significant difference between races on the issue of Iraq: fully 62% of white voters said they disapprove of the President's handling of the situation in Iraq, while 67% of black voters said they approve.

Following is the methodology, as provided by Landmark:

Landmark Communications, Inc. conducted this survey of 600 likely Georgia voters on August 20th and 21st, 2014. Telephone interviews were conducted by landline (80%) and mobile phone (20%). The phone list was created and randomized from Landmark Communications' own statewide Georgia voter database. Only completed interviews were included in the final report. Responses were weighted by age, gender and race to reflect the actual demographic make-up of a general election in Georgia in a gubernatorial election year. The margin of error is +/-4 percent. The survey was commissioned by WSB-TV Channel 2 Atlanta.