One thing’s for sure about this year’s Republican primary election for governor: Kelly Craft is dominating the airwaves.

Between Craft’s personal campaign and the political action committee supporting her, Commonwealth PAC, pro-Craft groups have spent at least $5.04 million on television and radio advertisements.

According to Medium Buying, which tracks Kentucky election advertisements, Republican gubernatorial candidates have spent over $10 million in the race, as of May 6.

Attorney General Danial Cameron trails behind Craft in spending. With the help of political action committee Bluegrass Freedom Action, pro-Cameron groups have spent $2.1 million on advertisements as of April 22.

Eric Deters’ campaign has also spent $147,300 to enter the airwaves.

According to Medium Buying, neither Ryan Quarles nor Alan Keck, the other candidates polling in the top five, had spent money on television and radio advertisements by April 22.

However, Quarles and Keck have both released digital advertisements since.

Quarles’ ad highlights his roots growing up on a family tobacco farm, and Keck’s positions himself as an alternative to the “same old politics.”

Another candidate, state auditor Mike Harmon, has released two digital ads on his campaign social media pages as of May 8, one which will briefly air on television, according to Harmon.

The pro-Craft, pro-Cameron and pro-Deters advertisements have adopted a more adversarial tone – towards each other, Gov. Andy Beshear and President Joe Biden.

Pro-Craft advertisements label Cameron as a “soft, establishment teddy bear.”

They also say that if elected, Craft would dismantle the Board of Education, which the Kentucky governor does not have the authority to do under current law.

Pro-Cameron ads have denounced Beshear for closing churches during the pandemic, touted his law enforcement endorsements and targeted Craft as “desperate” after she failed to get Trump’s endorsement.

Craft was not officially in the race at the time Cameron won the endorsement.

Political science research has revealed a correlation between campaign spending and election outcomes, but only to a point, and only in certain circumstances, said Dr. Stephen Voss, University of Kentucky associate professor and specialist in elections and voting behavior.

“Campaign spending brings diminishing returns, and it matters more for challengers than it does for incumbents,” Voss said.

“If a candidate, especially someone challenging an incumbent, lacks the funds needed to get a message out, the candidate’s usually doomed. But once the challenger’s spending enough to reach the electorate, then money stops mattering as much.”

The correlation between spending and success is much weaker when the source of campaign funds comes from a candidate’s own wealth, not donors or other outside sources, Voss said.

He added that in this correlation, the amount of spending may not necessarily be what’s causing a candidates’ success. Instead, major nonpartisan donors may want to back a winner, and so they may contribute to candidates they believe have the best chances.

According to one recent study, spending on advertisements is more likely to increase turnout by reaching voters with less information about an election than changing potential voters’ minds.

Advertisements will likely escalate in the final weeks before the primary election, as several campaign have paid for ad placements, mailers and digital advertisements in the past 15 days, according to the Kentucky Registry of Election Finance.

– Follow regional reporter Sarah Michels on Twitter @sarah_michels13 or visit bgdailynews.com.