More polls show the Liberals beginning to pull ahead of the Conservatives
Liberals 34%
Conservatives 28%
NDP 16%

Liberals 34%
Conservatives 31%
NDP 21%

With a week left in the campaign, the voters are beginning to make their final decisions on what their voting intentions are. It's possible to define voting intentions almost in a formulaic way. This formula would go something like this:

appetite for change + opinion of the alternative = voting intention indicator

The "appetite for change" variable includes such things as a person's opinion of the governing party, their personal happiness, and the media's treatment of the government.
A low voting intention indicator (I'll call it a VII because I'm lazy) should lead to a vote for the incumbent party. The higher the VII, the greater the chance of voting for one of the opposition parties.

Of course these are really just concepts, not numerical variables that can be measured easily, so I'm not going to try to treat them as numberical values.

Essentially these are the factors that parties are concerned with during an election. The governing party wants people to have a low VII, so they use positive campaign techniques like emphasizing portions of their record in power, as well as negative tactics such as criticizing the opposition.

Opposition parties tend to rely partially on positive tactics, which include strategically timed releases of portions of their campaign platform, but mostly they rely on negative campaign techniques, critizing and attacking the governing party's record and platform.

Other factors:
The more momentum a party has during an election campaign, the more comfortable they feel with the latest polling numbers for instance, the more that party will rely on positive tactics. As that party begins to fall behind, they start to shift towards negative tactics.

Some examples:
June 16
SES Conservative 34, Liberal 32
Ipsos-Reid Conservative 32, Liberal 31
Marzolini Conservative 36, Liberal 31
”If we continue to work hard in next few weeks. if we remain united, if we stick to our principles, if we continue to reach out to the supporters of other parties including all those disenchanted Liberals, we will be able to give Canadians a majority government we can all trust and be proud of.”
"I have asked Mr. Harper: that's fine, tell us what's going to give, tell us where you are going to find the $50 billion. And he has not been able to do so,"

June 22
SES Conservative 31, Liberal 34
Ipsos-Reid Conservative 28, Liberal 36
"He says health care is his No. 1 priority. The only time in the past decade it was his No. 1 priority is when he had to cut the budget. Then he cut health care first and he cut it deepest,"
"I feel very good about the way in which the whole race is unfolding. I feel very good about the realization of Canadians of the differences between Stephen Harper and myself on the issues of health care, childcare and the economy. They want a government that reflects their priorities, and reducing waiting times is their priority."

Computer problem, will finish post when I fix