New Manitoba election boundaries give upper hand to Progressive Conservatives, CBC News analysis finds

The Progressive Conservatives have an untold advantage in the lead up to the provincial election: the newly redrawn electoral boundaries benefit their party the most.

A CBC News analysis comparing outcomes of the 2011 and 2016 Manitoba general elections by applying the newly-aligned ridings shows the Progressive Conservatives would win an additional seat at the expense of the New Democratic Party in both contests when compared to the original ridings.

The analysis also found that many of the races where PC candidates lost to the NDP would have been much tighter under the new boundaries announced last year by the Manitoba Electoral Division Boundary Commission.

• How did we analyze these numbers?

2016 elections:  Fort Garry-Riverview flips blue

In 2016, NDP candidate James Allum edged out PC candidate Jeannette Montufar by only 301 votes out of nearly 9,200 cast ballots.

With the new boundaries, the Fort Garry riding sheds its Riverview neighbourhood, an area where nearly all polls overwhelmingly supported the NDP.

The effect of this change is a nearly 500-vote swing in favour of the PCs, handing them the seat with a slim margin of only 169 votes.

In Elmwood, the NDP would hold on to its seat, but it's already-slim victory margin of 107 votes slides to only 29 votes.

In northern Manitoba, the riding of Thompson was won by PC candidate Kelly Bindle by 358 votes, but under the new boundaries, that lead would have shrunk to only 86 votes. This erosion of PC support is mainly due to the fact that the riding of Thompson now extends to the extreme Northeastern part of the province, encompassing the NDP-friendly polling stations in Churchill and Gillam.

• Winnipeg getting another MLA, as Manitoba ridings redrawn for next provincial election
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However, changes to Southdale, located in the heart of Winnipeg's suburban swing ridings, significantly benefit the NDP in this upcoming election. The analysis shows the conservative candidate could lose a significant amount of support — upwards of 2,000 votes — now that the riding no longer includes Royal Wood, Island Lakes and Sage Creek. 

The exercise also shows that Green Party candidate David Nickarz may struggle to improve on or even match his 2016 second place showing now that Wolseley extends deeper into what was the now-defunct Minto riding where the Greens finished in fifth place, behind both the Liberals and even an independent.

2011 elections: Swan River goes from NDP to PC  

Despite the unprecedented outcome in 2016 where the PCs won a record-setting majority government with 40 of the provincial legislature's 57 seats, the effect of the new election boundaries holds true in 2011: a net benefit for the Progressive Conservatives.

Applying the new boundaries to the 2011 elections would cause the riding of Swan River to change hands from the NDP to the PCs. New Democrat Ron Kostyshyn won this riding in 2011, but with a realignment that now encompassses conservative-friendly towns like Roblin, Russel and Rossburn, it will be an uphill battle for any left-leaning party.

Slow stretch toward the suburbs

Christopher Adams, a political scientist based at St. Paul's College at the University of Manitoba, says these results highlight the gradual effect urban sprawl is having on the political landscape in Manitoba.

"It used to be the north side of Winnipeg was NDP, and the south was conservative or liberal, but in recent years it has not been about north versus south, but more an inner doughnut versus outer doughnut," he says.

Adams says former NDP leader Gary Doer is responsible for shifting politics to core versus suburb patterns in 1999 when he successfully wooed south Winnipeg's middle class voters.

But with the suburbs endlessly sprawling and taking up more space, Adams says the NDP's survival depends on moving its landlocked support from the core toward the city's extremities.

Boundary changes an independent process

Paul Thomas, professor emeritus of political studies at the University of Manitoba, has served on the Manitoba Boundary Commission at the federal level on three occasions.

He says the decisions made by these bodies are guided by criteria set forth in legislation and don't consider the impact changes could have on parties or individual candidates.

Unlike in the U.S. — where the redrawing of electoral divisions is often controlled by state legislators and governors, and therefore open to political manipulation — the boundary commission in Manitoba is non-partisan and operates independent of government on a fixed 10-year basis.

Thomas says while transposing past election results onto new boundaries can provide some insight into future outcomes, it can be unreliable because no two elections are exactly alike.

"Changed boundaries may have significant impacts on a few seats, but the overall impact is marginal in terms of deciding which party wins. Leadership, policy issues and the success of the campaign are far more important factors," he says.

Impact of boundary change can be significant

While the changes observed by the latest boundary changes are relatively minor, this is has not always been the case

Christopher Adams says that up until the 1960s the province's electoral system was heavily weighted to give more representation to rural voters. In his book, Politics in Manitoba: Parties, Leaders, and Voters, Adams describes how in 1952, 17 urban MLAs represented half of registered voters, whereas 40 rural MLAs represented the other half.

In 1968, an independent boundary commission proposed new adjustments to the rural-urban balance, resulting in nearly half of the province's ridings being located in Winnipeg. 

The following year in the 1969 general elections, Ed Schreyer led the NDP to its first ever victory.

How did we analyze these numbers?

This analysis, also known as a "vote transposition," is a calculation used by agencies and political parties to understand how changes to electoral boundaries could impact outcomes in subsequent elections.

The exercise essentially answers the question: If the new riding boundaries were used in a previous election, how would the outcome change?

Elections results at the polling level were used and then superimposed with the new riding map to determine how to distribute past results to the new ridings. 

To illustrate the process, the red boundary below represents a riding, inside of which there are six polling areas where constituents cast their votes.

When new boundaries are redrawn, sometimes a polling area ends up being split in half by the boundaries of the new ridings. In the case below, the two voting areas in the middle are split 50/50 and so the votes in the voting areas that were part of the original riding are now split and divvied up between the two new ridings.

However sometimes, part of a voting area that now falls within a new riding doesn't actually contain any voters. This could be because of commercial space, parks, agricultural land or an airport, among other things. In these cases, we don't want to include the surface area in the calculation for determining how to divide up the votes between the new ridings.

To account for this, the analysis relied on a Manitoba-wide property parcel map to eliminate all areas in the province where there is not a residential parcel. In the image below, it is clear that it wouldn't make sense to assign votes to a riding, if there are no voters that live in the area being split.

In addition, an increasing number of Manitobans don't vote at a polling station on election day. For advance voters, write-in ballots and other non-election-night voting methods, the results were divvied up proportionally across the electoral division's voting areas.

Unlike political parties, members of the public and media do not have access to voter lists that contain, among other things, the exact home addresses of each registered voter. With this information, an even more accurate analysis could be done.

Transposition of 2016 votes onto new ridings

The table below provides the vote share by party for each constituency after transposing the results of the 2016 Manitoba general election onto the new election boundaries established in 2018.

This 2018 map is the one in effect for the Sept. 10, 2019, election.

The figures below do not reflect the results of the byelections held in Point Douglas in 2017 and St.Boniface in 2018.

Data for the analysis includes historic polling area results and boundary files from Elections Manitoba, property parcel maps from the City of Winnipeg and the Province of Manitoba.

Calculations and analysis by CBC News data journalist Jacques Marcoux using Python and PostGIS.