Ohio University study says speeches at Democratic and Republican conventions were more attack-laden than ever

Barack Obama and Mitt Romney's acceptance speeches at the Democratic and Republican conventions were far more attack-laden than those of their predecessors, according to a new analysis by an Ohio University professor.

In an election cycle which has been notable for the intensity of negative advertising, the study shows that Obama and Romney took this trend on to the podium as they exceeded the average for attacks in elections going back to 1952.

Some 27% of the president's speech was devoted to attacking Romney or the Republicans – much higher than the average of 16% attacks in an incumbent's acceptance address. Similarly, 38% of Mitt Romney's address was composed of attacks on Obama – compared to an average 30% for a challenger's speech.

Fuelled by millions of dollars-worth of negative advertising by outside groups in battleground states, the 2012 campaign has been described as one of most negative ever, a trend that began with the Republican primaries.

While campaigns supporting both Romney and Obama pulled negative advertisements on September 11, such advertisements are expected to run non-stop in swing states from now until the 6 November election.

The study was conducted by Bill Benoit, professor of communication studies at Ohio University, who examined acceptance addresses given by Democratic and Republican nominees dating back to 1952.

Benoit split the speeches into those given by "incumbents" (presidents seeking a second term) and "challengers" (party nominees attempting to win the presidency). On breaking down individual statements made in the speeches into "acclaims" or "attacks", Benoit found that an incumbent's acceptance address to a party convention is, on average, made up of 84% of acclaims – the president making a positive statement about his or her policies or image – and 16% of attacks – the president making a negative remark about the opponent or the opponent's party.

The research shows that Obama's convention speech in Charlotte, North Carolina strayed from the average for an incumbent president. Seventy-three per cent of his address was made up of acclaims and 27% of attacks, implying a more negative tone to his address than might be expected from an incumbent president.

On average, challengers' speeches are more attacking than an those of an incumbents, given the need for a challenger to speak about how the president is performing poorly in order to convince people of the need for change. In elections between 1952 and 2012, challengers spent 70% of their address acclaiming their own record or achievements and 30% attacking their opponent or their opponent's party.

Even by these standards, Romney was unusually negative this year, with just 62% of his speech in Tampa, Florida being devoted to praising his own record.

Benoit said the more negative speeches may be the result of both Obama and Romney attempting to "throw red meat" to their supporters, in a bid to encourage donations.

"By and large most of the people who watch acceptance addresses are partisan," he said. "They've probably decided they need to appeal to their base."

Benoit also looked at whether Obama and Romney's acclaims and attacks had focused on policy or character issues. He found that Romney spent 55% of his speech talking about character – both his and Obama's – and 45% discussing policy. On average, a challenger devotes 50% of the address to tackling policy matters.

Obama discussed character in 42% of his speech and devoted 58% of the address to policy – exactly in line with the average statistics for an incumbent president.

© Guardian News and Media 2012