Doug Ford's Progressive Conservatives scored a convincing win in last week's Ontario election, taking 61 per cent of the seats — but with only 40 per cent of the vote.

Meanwhile the third-place Liberals, who got 20 per cent of the vote, earned just six per cent of the seats.

For voters wondering how that can happen, the answer lies in Ontario's electoral system, a method known as first-past-the-post, or single-member plurality.

In each riding, the candidate who wins the highest number of votes wins the seat, even if they don't have more than 50 per cent support. That's why defeated premier Kathleen Wynne won her riding of Don Valley West with only 39 per cent of the ballots. And it's why the PCs gained a majority at Queen's Park with considerably less than half the votes.

"As soon as you explain this to anybody, they are outraged. They are as outraged as if in the House you were to pass a bill and only 40 per cent of the House was enough," said Réal Lavergne of Fair Vote Canada, a group campaigning for a more proportional voting system. "And that's essentially what's happening here."

All provincial and federal elections in Canada currently unfold this way. But that hasn't always been the case, and a number of provinces — including Ontario — have considered changing in recent years.

What would the Ontario election results have looked like under a different voting method? CBC News used Elections Ontario's poll-by-poll results to find out, simulating the outcome under three different systems: pure proportional representation, mixed-member proportional and mixed-member majoritarian.

Our experiment reshuffled the seats at Queen's Park in a dramatic way.

Scenario 1: Pure proportional representation

Proportional representation is considered to be the most common electoral system among well-established democracies, from Austria to Uruguay and dozens in between. It was also one of the scenarios considered by Prime Minister Justin Trudeau, before his government dropped the idea of federal electoral reform in 2017.

In its purest form, proportional representation is very simple: parties are given seats based on the percentage of the popular vote they obtain.

Since Doug Ford's PCs won roughly 40 per cent of the popular vote in last week's Ontario election, they would get 51 of the 124 seats in the legislature — short of the 63 needed to form a majority government.

Under the same system, the Ontario Liberals would have obtained three times more seats, while the NDP's numbers would have remained the same. Green Party Leader Mike Schreiner, elected in the riding of Guelph, would have gotten a whole posse to join him at Queen's Park too, since 4.6 per cent of the popular vote equals roughly six seats.

"These results are radically different," Fair Vote Canada president Réal Lavergne said. Under proportional representation, "you're more likely to have four or five dominant parties and those parties have to create coalitions ... Decisions have to be made by consensus."

All of this would have created an opportunity for a potential coalition government.

"Of course, with a different system, people might have voted completely differently," acknowledged York University politics professor Dennis Pilon, who has written two books on voting systems.

But proportional representation also has its failings. In Israel, for example, governments tend to be unstable because the large number of coalition parties can't always agree, often leading to early elections.

Scenario 2: Mixed-member proportional

If Ontarians voted under mixed-member proportional representation, voters would cast two ballots: one for a local MPP to represent their riding, and one for the party of their choice. In some cases, that second ballot can also be cast for a regional candidate.

Most of the seats in the legislature would be held by locally elected MPPs. But a significant chunk of other seats — as much as a third of the legislature — would be used to "top up" some parties to better reflect the popular vote. In last week's election, where the Liberals got 20 per cent of the vote but six per cent of the seats, they would have received a top-up of 16 seats, using a common type of MMP.

New Zealand, Germany and Scotland have versions of this system.

MMP isn't a new concept in Canada. In 2004, the Law Commission of Canada recommended it in a report evaluating alternatives for the House of Commons. It was also rejected in an electoral reform referendum in Ontario in 2007. The New Democratic Party of Canada has been a longtime supporter of MMP, calling it the best way "to make every vote count."

Scenario 3: Parallel voting

Parallel voting, also known as mixed-member majoritarian, was also considered in 2004. It's how Japanese, South Korean, Taiwanese and now Italian voters elect their governments.

Voters elect a percentage of members in the legislature using the first-past-the-post system, and another portion is elected by pure proportional representation.

If Ontarians voted using a parallel system with one-third of the seats being proportional, they would still have a majority Conservative government with 68 seats, along with 40 seats for the NDP. The Liberals would score nearly twice as many seats though, and the Greens would have a caucus of three MPPs.

Hard to get reform, critics says

No matter which proportional model is used, York University's Pilon says, it would reflect voter's choices better than the current first-past-the-post system.

But there are other factors to consider. After coming to power on a promise of electoral reform, the federal Liberal government now defends first-past-the-post, while acknowledging it's "not perfect."

"It has served this country for 150 years and advances a number of democratic values that Canadians hold dear, such as strong local representation, stability and accountability," Minister of Democratic Institutions Karina Gould said last year at a parliamentary committee hearing.

No matter who's in power, changing voting systems in Canada would be difficult, Fair Vote Canada's Lavergne says. "Electoral reform depends on those who are elected to power under the current system, to change the system. They don't have any incentive to do that."