A university study argues that advertising messaging played a role in Hillary Clinton's loss to Donald Trump in the 2016 US Presidential Election.

Researchers for the Wesleyan Media Project said that Clinton's advertisements were 'devoid of policy discussions in a way not seen in the previous four presidential contests' and urge 'caution in concluding that television advertising is no longer effective'.

The study found that only about 25 percent of Clinton's advertising focused exclusively on policy, compared to the 70 percent of Trump ads that discussed just policy.

Meanwhile, Clinton's team devoted more than 60 percent of its ads to 'personal' issues such as candidate characteristics.

About 10 percent of Clinton ads and 15 percent of Trump ads focused on a mixture of policy and personal.

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A study published by the Wesleyan Media Project at Wesleyan University found that Hillary Clinton's television advertisements were, on measure, 'devoid of policy discussions in a way not seen in the previous four presidential contests.' Pictured: A Clinton ad

Study found that Clinton's team devoted 25 percent of TV ads exclusively to policy while 70 percent of Trump's ads discussed policy. Found that almost half of her ads were negative, denigrating Trump, while more than half of Trump's provided 'contrast,' denigrating Clinton while propping him up

For comparison, in 2012 the percentage of both Obama and Romney ads that focused exclusively on personal issues was no more than 10 percent.

And in 2000, when George W. Bush defeated Al Gore, hardly any ads were devoted to exclusively 'personal' issues.

The Project, which is housed at Wesleyan University in Connecticut and analyzes all broadcast ads from politicians, illustrates how the 2016 campaign featured significantly fewer advertisements than 2012's cycle, in which Barack Obama won a second term by defeating Republican candidate Mitt Romney.

The cycle last year featured just under 600,000 advertisements in the top 75 media markets, compared to more than 900,000 in 2012 and slightly more than 600,000 in both 2008 and 2004.

This graph illustrates Clinton's failure to broadcast ads until the last week of the campaign in two swing states that she lost: Michigan and Wisconsin. Her ads in Pennsylvania, which she also lost, skyrocketed in the last week too

The researchers found, in essence, that Clinton's advertisements were too focused on negative characteristics of Donald Trump and not enough on positive policy changes she would effect if she became president. Pictured: A Clinton ad

Researchers found that almost half of Clinton ads were negative - meaning their purpose was primarily to denigrate Trump - while more than half of Trump's ads were 'contrast' spots that denigrated Clinton but also contrasting her with himself.

An example of a 'personal' ad is Clinton's 'Role Models' commercial, in which little girls listened to misogynistic comments from Trump.

Trump's 'Two Americas,' advertisement, which described what his team claimed would be the difference between 'Hillary's America' and 'Trump's America,' was a 'contrast' spot.

Clinton was found to have focused on 'personal' television advertisements, for example her ad 'Role Models,' in a way that was unprecedented and not matched by Trump. Researchers said: 'Team Clinton's message that Trump was unfit for the presidency may not have been enough'

The researchers also concluded that of the Clinton ads denigrating Trump, about 90 percent of them focused on his personal characteristics, for example, his temperament and comments towards women.

Meanwhile, less than 10 percent focused on his proposed policies - for example, building a wall along the Mexico or his proclamation to 'bomb the s*** out of ISIS.

In essence, the study found that Clinton's advertisements did not focus on positive policy changes she would effect if she became president.

This graph shows Clinton's considerable advantage on broadcast television's top 75 media markets, with darker shading reflecting a greater advantage. Note Trump's advantage in Wisconsin, where he won by less than 25,000 votes

The researchers wrote: 'Message matters, and a message repeated endlessly does no good unless it resonates with a sufficient number of the right voters.

'Team Clinton's message that Trump was unfit for the presidency may not have been enough.'

The study also commented on the 'unusual nature' of the 2016 race - both due to Trump being an outsider candidate and Clinton's significantly different campaign tactic of focusing heavily on his seemingly unfit presidential credentials and temperament.

Donald Trump won the 2016 election with 306 pledged electors out of the 538 in the US Electoral College. He carried 30 states, compared to Clinton's 20 plus her win in the nation's capital.

Clinton won the popular vote, with about 65.9million votes compared to Trump's 63.0million.