Hillary Clinton gets convention bump and a little help from Donald Trump

Hillary Clinton is coming out of last week's Democratic National Convention with soaring poll numbers just as Donald Trump's campaign is hobbled by one self-inflicted wound after another.

In less than a week, Trump has managed to claim that the upcoming election will be "rigged", attack the father of a slain Muslim American soldier, and claim that Russia is not involved in Ukraine. And these are just a few examples of what has made the last few days a tough one for the Republican nominee.

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There is no doubt that Trump made some gains in the wake of the Republican National Convention and the naming of Indiana Gov. Mike Pence as his vice-presidential running mate. But if his convention bump was typical, it is beginning to look small compared to Clinton's convention boost.

Based on polls from six polling firms conducted at least partially after the end of the Democratic convention, it appears that Clinton's campaign has received a boost of almost nine points. Support for her candidacy has increased by about 4.5 points, on average, while Trump's has slipped by 4.3 points.

Though convention boosts occur in almost every U.S. election campaign, this one is on the higher side. It might fade quickly, but recent days have not suggested that Trump is on pace to make gains.

Clinton's favourability ratings have also improved, increasing by an average of four points to 41 per cent in recent polls. Her unfavourability remains greater, at an average of 53 per cent, but that is down four points from the pre-convention period.

This has restored her numbers to where they were before the two conventions, when Trump was the more unpopular candidate of the two. But from an average favourability of 38 per cent after the end of the Republican event in Cleveland, Ohio, Trump's favourability has now slipped again to just 34 per cent. An average of 59 per cent of Americans say they hold an unfavourable view of the Republican nominee.

Clinton advantage widens

The Presidential Poll Tracker, which reacts to swings in polling more slowly at this stage of the campaign than it will as the election approaches, has shown an improvement in Clinton's standings.

She is pegged to have the support of 45.7 per cent of decided voters, compared to 41.9 per cent for Trump. 

At the height of Trump's post-convention surge, he trailed the Democratic nominee by just two points. But that gap has widened once again to about four points — virtually identical to where it stood on July 17, before the Republican convention kicked off.

Support for third party candidates stands at 12.4 per cent. Libertarian candidate Gary Johnson has averaged 7.5 per cent support in the last week of polling, while Green candidate Jill Stein has averaged three per cent.

Based on where the two major candidates stand at the state level, where the election will be decided, Clinton is currently projected to win between 256 and 363 electoral college votes. Trump is projected to win between 175 and 282 votes. A total of 270 votes are required to win the presidency.

(Scroll to the end of this article to see the full breakdown of the electoral college map.)

Clinton leads in most battleground states

The Presidential Poll Tracker model considers eight states to be virtual toss-ups at this stage. Clinton leads in six of them (Florida, Iowa, Nevada, North Carolina, Ohio, and Virginia). Trump is ahead in two others (Georgia and New Hampshire).

Georgia is not normally a swing state. It has not voted for a Democrat since Bill Clinton in 1992, but now might be trending towards another Clinton in this election cycle. In a state Trump should be winning by seven points (based on the margin between the two candidates nationwide), two polls by Landmark Communications have put Trump up by one point or in a tie. Another poll by SurveyUSA had Trump ahead by just four points.

On the other hand, New Hampshire and Nevada are trending more towards Trump. In New Hampshire, one recent poll put Clinton and Trump in a tie while another put Trump up by 10 points. Going by national numbers, this is a state that Clinton should be winning by six points.

Nevada, another state Clinton should be winning by six points, has seen one recent poll by Monmouth University giving her an edge of five points, while two polls by Rasmussen have put her ahead by just one point or behind by five.

But the most important battleground states — Florida, North Carolina, Ohio, and Virginia, along with Pennsylvania — are currently leaning towards Clinton. If she continues to see her poll numbers improve in the wake of last week's convention in Philadelphia, her advantage in these battleground states will widen as well.

And if Clinton manages to hold on to most of her over-sized convention bounce in the coming weeks, Trump may have too much ground to make up. 

The Presidential Poll Tracker includes all published mainstream surveys, a list of which can be found here. The polls are weighted by sample size and date, as well as the reliability of each pollster as rated by FiveThirtyEight.com. The electoral college is projected by applying the same weighting standards to state-level polls and combining this with a uniform swing model, based on how the current national polling average compares with the 2012 presidential election. Surveys included in the model vary in terms of sample size and methodology and have not been individually verified by the CBC. A full methodological explanation can be found here.