A real estate consultant’s warning that housing market data in Canada is being artificially inflated has some economists and market observers wondering whether the recent upswing in house sales and prices might be partly an illusion.

Real estate consultant Ross Kay alleges that realtors in certain parts of the country — particularly in Greater Toronto and southern Ontario — are artificially inflating home sales by listing the same property twice, or sometimes even three times.

Kay says when a double- or triple-listed house like this sells, the additional listings are counted as a sale by every one of the real estate boards to which the house is assigned. That turns one sold house into two or three sales in the housing data.

The end result, Kay argues, is that reported home sales and house price numbers are higher than they really are.

“Statistically valid month-over-month comparisons on sales volumes are inflated as much as 15 per cent in some cities in 2013,” he told HuffPost in an email. “Average prices are skewed upward as much as 10 per cent some months.”

This screencap of homes for sale in Oakville, Ont., as of last Friday, shows a significant proportion of houses have “phantom listings.”

mls oakville

Ross Godsoe, CEO of the Realtors Association of Hamilton-Burlington, said Kay is “probably correct” in his claim that houses are being double- and triple-counted.

He told HuffPost Canada that any house listed in his area — even if it is listed elsewhere — would count towards the monthly sales numbers.

Godsoe could not say whether other real estate boards operated the same way. Calls to several other real estate boards in southern Ontario were not returned as of press time.

Under Ontario’s realty rules, realtors can’t be prohibited from listing houses in areas other than their own, Godsoe said.

“If a sale occurs, we’re obligated to report that,” he said, adding he did not know what the Canadian Real Estate Association (CREA) does with the numbers once it receives them.

CREA’s monthly numbers are arguably the most closely watched indicator of housing market health.

Story continues below slideshow

Loading Slideshow...
  • 12 Degrees

    This 11-story building near Toronto's Queen West, developed by BSäR Group Of Companies and Prince Bay Developments, is meant to reflect the "building-block" feel of other buildings in the neighbourhood, such as the Art Gallery of Ontario and the Ontario College of Art and Design. Expected completion date: January 2013.

  • 12 Degrees

    This 11-story building near Toronto's Queen West, developed by BSäR Group Of Companies and Prince Bay Developments, is meant to reflect the "building-block" feel of other buildings in the neighbourhood, such as the Art Gallery of Ontario and the Ontario College of Art and Design. Expected completion date: January 2013.

  • 12 Degrees

    This 11-story building near Toronto's Queen West, developed by BSäR Group Of Companies and Prince Bay Developments, is meant to reflect the "building-block" feel of other buildings in the neighbourhood, such as the Art Gallery of Ontario and the Ontario College of Art and Design. Expected completion date: January 2013.

  • West Harbour City

    Completed in 2010, this building on Toronto's western lakeshore gives the city a new Gothic touch. Developed by Plazacorp and designed by Quadrangle Architects, the 36- and 28-story condo towers are quickly becoming a city landmark.

  • West Harbour City

    Completed in 2010, this building on Toronto's western lakeshore gives the city a new Gothic touch. Developed by Plazacorp and designed by Quadrangle Architects, the 36- and 28-story condo towers are quickly becoming a city landmark.

  • Hive Lofts on the Queensway

    Designed by Teeple Architects and developed by Symmetry Developments, this six-story low-rise will change the feel of Toronto's Queensway neighbourhood. Construction expected to be completed by May, 2013.

  • Hive Lofts on the Queensway

    Designed by Teeple Architects and developed by Symmetry Developments, this six-story low-rise will change the feel of Toronto's Queensway neighbourhood. Construction expected to be completed by May, 2013.

  • TCHC Block 32

    OK so this isn't exactly a condo tower -- it's a rental building being developed by the Toronto Community Housing Corporation. The 41-story apartment building is set to be completed in late 2012, and the building makes two important points: That rental aprtment buildings can have character; and that if designed properly, buildings can look cool in winter.

  • TCHC Block 32

    OK so this isn't exactly a condo tower -- it's a rental building being developed by the Toronto Community Housing Corporation. The 41-story apartment building is set to be completed in late 2012, and the building makes two important points: That rental aprtment buildings can have character; and that if designed properly, buildings can look cool in winter.

  • 190OZ

    190OZ, to be located on Ossington Street in the city's west side, is another example of the "building block" style that is becoming popular in Toronto. Developed by Reserve Properties, the six-story building should be online in 2014.

  • 190OZ

    190OZ, to be located on Ossington Street in the city's west side, is another example of the "building block" style that is becoming popular in Toronto. Developed by Reserve Properties, the six-story building should be online in 2014.

  • King West Condominiums

    This monstrous, three-pronged condo tower isn't slated to open until mid-2013, but its shadow is already changing Toronto's landscape. Developed by Plazacorp and designed by Quadrangle Architects, the building features a 20,000-square-foot fitness club and no fewer than two bowling alleys.

  • King West Condominiums

    This monstrous, three-pronged condo tower isn't slated to open until mid-2013, but its shadow is already changing Toronto's landscape. Developed by Plazacorp and designed by Quadrangle Architects, the building features a 20,000-square-foot fitness club and no fewer than two bowling alleys.

  • King West Condominiums

    This monstrous, three-pronged condo tower isn't slated to open until mid-2013, but its shadow is already changing Toronto's landscape. Developed by Plazacorp and designed by Quadrangle Architects, the building features a 20,000-square-foot fitness club and no fewer than two bowling alleys.

  • Edge on Triangle Park

    This 15-story building from Plazacorp and architects Tact Design brings European modernism to Toronto's Liberty Village neighbourhood. The big empty spaces in the building (note the gap on the right side of the main facade) create a "shine-through" effect that gives the building more than the usual amount of lighting. Completion slated for January, 2014.

  • Edge on Triangle Park

    This 15-story building from Plazacorp and architects Tact Design brings European modernism to Toronto's Liberty Village neighbourhood. The big empty spaces in the building (note the gap on the right side of the main facade) create a "shine-through" effect that gives the building more than the usual amount of lighting. Completion slated for January, 2014.

  • Studio on Richmond

    Aspen Ridge Homes is planning this futuristic (some would even say Blade Runner-ish) building complex for Toronto's repidly gentrifying downtown east side. Once completed, the complex will feature two towers -- one 41 stories, the other 31 stories. Another project from Quadrangle Architects, this one is slated for completion in January, 2015.

  • Studio on Richmond

    Aspen Ridge Homes is planning this futuristic (some would even say Blade Runner-ish) building complex for Toronto's repidly gentrifying downtown east side. Once completed, the complex will feature two towers -- one 41 stories, the other 31 stories. Another project from Quadrangle Architects, this one is slated for completion in January, 2015.

  • Studio on Richmond

    Aspen Ridge Homes is planning this futuristic (some would even say Blade Runner-ish) building complex for Toronto's repidly gentrifying downtown east side. Once completed, the complex will feature two towers -- one 41 stories, the other 31 stories. Another project from Quadrangle Architects, this one is slated for completion in January, 2015.

  • Fashion House

    Fashion House incorporates a heritage building on Toronto's King Street West into a modern condo and retail complex. Designed by Core Architects and developed by Freed Developments, the building is one of Toronto's most unique restorations of a historical building.

  • Fashion House

    Fashion House incorporates a heritage building on Toronto's King Street West into a modern condo and retail complex. Designed by Core Architects and developed by Freed Developments, the building is one of Toronto's most unique restorations of a historical building.

  • Fashion House

    Fashion House incorporates a heritage building on Toronto's King Street West into a modern condo and retail complex. Designed by Core Architects and developed by Freed Developments, the building is one of Toronto's most unique restorations of a historical building.

  • Emerald Park

    Yes, people will be living in the curvy parts at the top, and what a downward view they'll have. This condo complex in north Toronto (401 and Yonge St.) will feature twin 42- and 43-story towers, and is slated for completion in August, 2013. It was developed by Metropia, Pure Plaza, and the architect is Roy Varacalli.

  • Emerald Park

    Yes, people will be living in the curvy parts at the top, and what a downward view they'll have. This condo complex in north Toronto (401 and Yonge St.) will feature twin 42- and 43-story towers, and is slated for completion in August, 2013. It was developed by Metropia, Pure Plaza, and the architect is Roy Varacalli.

  • Emerald Park

    Yes, people will be living in the curvy parts at the top, and what a downward view they'll have. This condo complex in north Toronto (401 and Yonge St.) will feature twin 42- and 43-story towers, and is slated for completion in August, 2013. It was developed by Metropia, Pure Plaza, and the architect is Roy Varacalli.

  • X The Condominium

    Designed by architectsAlliance for Great Gulf Homes, this building is recognizable to many Torontonians as an homage to the smoky black TD Bank tower on the city's skyline. Interesting as the building is, we're hoping the trend doesn't catch on, or the city will become a forest of black rectangles.

  • X The Condominium

    Designed by architectsAlliance for Great Gulf Homes, this building is recognizable to many Torontonians as an homage to the smoky black TD Bank tower on the city's skyline. Interesting as the building is, we're hoping the trend doesn't catch on, or the city will become a forest of black rectangles.

  • X The Condominium

    Designed by architectsAlliance for Great Gulf Homes, this building is recognizable to many Torontonians as an homage to the smoky black TD Bank tower on the city's skyline. Interesting as the building is, we're hoping the trend doesn't catch on, or the city will become a forest of black rectangles.

  • The Schoolhouse Lofts

    The Schoolhouse is an example of creative urban land use. Once known as Loretto College, the building has been transformed from a school into a five-story loft and condo complex in the heart of Toronto's Annex neighbourhood. Designed by 3rd Uncle for Empire Communities, the building opened in March, 2010.

  • The Schoolhouse Lofts

    The Schoolhouse is an example of creative urban land use. Once known as Loretto College, the building has been transformed from a school into a five-story loft and condo complex in the heart of Toronto's Annex neighbourhood. Designed by 3rd Uncle for Empire Communities, the building opened in March, 2010.

  • The Schoolhouse Lofts

    The Schoolhouse is an example of creative urban land use. Once known as Loretto College, the building has been transformed from a school into a five-story loft and condo complex in the heart of Toronto's Annex neighbourhood. Designed by 3rd Uncle for Empire Communities, the building opened in March, 2010.

  • Seventy5 Portland

    Another building from Freed Developments and Core Architects, this low-rise near King and Bathurst has garnered a lot of attention for its irregular rectangular patterns. The 10-story condo building opened in 2010.

  • Seventy5 Portland

    Another building from Freed Developments and Core Architects, this low-rise near King and Bathurst has garnered a lot of attention for its irregular rectangular patterns. The 10-story condo building opened in 2010.

  • Market Wharf

    Architect Peter Clewes' project near St. Lawrence Market on the east side of downtown has gotten a lot of attention for blending a style that evokes the surrounding historic buildings, while throwing a modernist tower -- complete with crazy, wavy balconies -- into the city skyline. Developed by Context Developments, the building opened in 2012.

  • Market Wharf

    Architect Peter Clewes' project near St. Lawrence Market on the east side of downtown has gotten a lot of attention for blending a style that evokes the surrounding historic buildings, while throwing a modernist tower -- complete with crazy, wavy balconies -- into the city skyline. Developed by Context Developments, the building opened in 2012. (Photo: Tact Design)

  • Market Wharf

    Architect Peter Clewes' project near St. Lawrence Market on the east side of downtown has gotten a lot of attention for blending a style that evokes the surrounding historic buildings, while throwing a modernist tower -- complete with crazy, wavy balconies -- into the city skyline. Developed by Context Developments, the building opened in 2012. (Photo: Tact Design)

  • Theatre Park

    One of the coolest aspects of this very noticeable building is how not noticeable at all it is at ground level -- it appears to be just another small building on King Street West. Designed by architectsAlliance for Lamb Developments, the building is slated for completion in 2013.

  • Theatre Park

    One of the coolest aspects of this very noticeable building is how not noticeable at all it is at ground level -- it appears to be just another small building on King Street West. Designed by architectsAlliance for Lamb Developments, the building is slated for completion in 2013.

  • Theatre Park

    One of the coolest aspects of this very noticeable building is how not noticeable at all it is at ground level -- it appears to be just another small building on King Street West. Designed by architectsAlliance for Lamb Developments, the building is slated for completion in 2013.

  • The Printing Factory

    Another example of creative land use, this time in Leslieville on the city's east side. Architects Chandler Graham and Montgomery Sisam redesigned this defunct factory into modern lofts for Beaverbrook Homes, adding a tower that rises from the centre of the old print shop. The condo complex opened in 2010.

  • The Printing Factory

    Another example of creative land use, this time in Leslieville on the city's east side. Architects Chandler Graham and Montgomery Sisam redesigned this defunct factory into modern lofts for Beaverbrook Homes, adding a tower that rises from the centre of the old print shop. The condo complex opened in 2010.

  • Picasso

    This may well become the most iconic of Toronto's new generation of "building block" condos, rising above Richmond Street West, near similarly lego-shaped buildings like OCAD. Teeple Architects designed this for Monarch and the Goldman Group, and the building is slated to finish construction in January, 2015.

  • Picasso

    This may well become the most iconic of Toronto's new generation of "building block" condos, rising above Richmond Street West, near similarly lego-shaped buildings like OCAD. Teeple Architects designed this for Monarch and the Goldman Group, and the building is slated to finish construction in January, 2015.

  • Pier 27

    Four 14-story buildings, connected by skywalks, are at the heart of what may be the most bold and unique condo development in Canada -- Pier 27, which is currently under construction and is already changing the face of Toronto's grimy eastern lakeshore. Designed by architectsAlliance for Cityzen and Fernnbrook Homes. Watch for this building to win awards.

  • Pier 27

    Four 14-story buildings, connected by skywalks, are at the heart of what may be the most bold and unique condo development in Canada -- Pier 27, which is currently under construction and is already changing the face of Toronto's grimy eastern lakeshore. Designed by architectsAlliance for Cityzen and Fernnbrook Homes. Watch for this building to win awards.

  • Pier 27

    Four 14-story buildings, connected by skywalks, are at the heart of what may be the most bold and unique condo development in Canada -- Pier 27, which is currently under construction and is already changing the face of Toronto's grimy eastern lakeshore. Designed by architectsAlliance for Cityzen and Fernnbrook Homes. Watch for this building to win awards.

  • The L-Tower

    Designed by world-renowned architect Daniel Liebeskind, this 58-story condo tower will rise above the Sony Centre for the Performing Arts on Front Street. Being so close to the business district, the building's unique shape (it grows wider at the top, leaning out onto the street) will alter the city skyline permanently. The original design for the building called for a large open hole at the base of the "L" shape, but more recent illustrations suggest that part of the plan has been scaled back.

  • L-Tower

    Designed by world-renowned architect Daniel Liebeskind, this 58-story condo tower will rise above the Sony Centre for the Performing Arts on Front Street. Being so close to the business district, the building's unique shape (it grows wider at the top, leaning out onto the street) will alter the city skyline permanently. The original design for the building called for a large open hole at the base of the "L" shape, but more recent illustrations suggest that part of the plan has been scaled back.

  • L-Tower

    Designed by world-renowned architect Daniel Liebeskind, this 58-story condo tower will rise above the Sony Centre for the Performing Arts on Front Street. Being so close to the business district, the building's unique shape (it grows wider at the top, leaning out onto the street) will alter the city skyline permanently. The original design for the building called for a large open hole at the base of the "L" shape, but more recent illustrations suggest that part of the plan has been scaled back.

  • L-Tower

    Designed by world-renowned architect Daniel Liebeskind, this 58-story condo tower will rise above the Sony Centre for the Performing Arts on Front Street. Being so close to the business district, the building's unique shape (it grows wider at the top, leaning out onto the street) will alter the city skyline permanently. The original design for the building called for a large open hole at the base of the "L" shape, but more recent illustrations suggest that part of the plan has been scaled back.

  • Absolute World

    The Absolute Towers at Mississauga's Square One (also known as the "Marilyn Monroe" towers) are arguably the most celebrated new buildings in the Toronto area, having won an award for "Best Tall Building in the Americas" for 2012. Designed by MAD Architects for Cityzen and Fernbrook Homes, the twin buildings were completed in late 2011. So it appears that Mississauga's long struggle to climb out of Toronto's shadow may have borne some fruit at last.

CREA spokesman Pierre Leduc told HuffPost the association checks the data coming from local boards to ensure houses aren't double-counted. That contradicts what Kay and others have said — that CREA only gets aggregate numbers from the boards, and has no way of telling whether houses are being double-counted.

“CREA takes the amalgamated data … from over 70 regional MLSs and adds it up and reports on it — no addresses are ever provided — without the ability to audit the data,” Kay told HuffPost in an email.

UPDATE: In a follow-up conversation, Leduc clarified that most real estate boards send the association only aggregate data, meaning CREA would not know if houses are double-counted. But for the handful of cities used in its house price index, CREA checks the data to eliminate double-counted houses, Leduc said.

CREA chief economist Gregory Klump could not say if CREA's data included double-counted houses. But he estimated the phantom listings account for no more than 0.8 per cent of the housing supply available.

Godsoe of the Hamilton-Burlington board similarly said any effect phantom listings would have would be “very minor.” He said he is "absolutely" confident in the reliability of his real estate board's numbers.

At the local level, the impact can still be significant. If a significant proportion of houses have double listings in places like Oakville, that could cause meaningful changes in house sales numbers for Hamilton, the Peel region and Greater Toronto.

And because the Toronto area is weighted so heavily in house price indices, it could be distorting national data as well.

In his own audit of CREA’s data, Kay said there were 2,902 more home listed as sold than there really were in August of this year. While CREA reported 40,315 homes sold in Canada in August, Kay’s audit found sales were only 37,413 — a difference of 7.2 per cent.

While CREA’s numbers report home sales in total are down 2.9 per cent for the year to date, compared to the same period last year, Kay’s audit found a decline in sales of 9.6 per cent this year so far.

Housing "remains fully in a full market correction phase," Kay concluded on his website.

Kay’s claims have some economists wondering about CREA’s numbers.

BMO economist Benjamin Reitzes noted the controversy in a client note Monday morning, and told HuffPost Canada he found that the sales numbers from the local Toronto-area boards compared to stats from CREA “were off just a little bit."

But Reitzes and other market observers said the practice was unlikely to raise house price numbers, because it increases the apparent supply of available houses as much as it increases the sales numbers.

Kay disagrees. He says the double- and triple-listings are concentrated more at the top of end the housing market, and those increased “sales” at the top end are pulling up the average house price.

Kay says the entire practice is possible because “the MLS infrastructure legally requires silence and non-disclosure of any fact that could negatively impact any active listing on the MLS or any of its members.” He says this has become a massive problem in reporting MLS data since 2010.

BMO’s Reitzes, like some other market observers, highlights another potential area of unreliability. He says he was told by CREA that the association doesn’t adopt revisions made to earlier numbers from local real estate boards — something he calls “a bit of a red flag” on the data.

Canada’s housing market has been showing surprising strength in recent months, after a slowdown last year following the introduction of tougher mortgage rules.

CREA’s own numbers, released Monday, show home sales rising 11.1 per cent nationally in August from the same month a year earlier.

The Toronto Real Estate Board reported a 21-per-cent jump in house prices from a year earlier for August, while Vancouver saw sales soar a stunning 52.5-per-cent jump in the same period, according to its local real estate board. There are few “phantom listings” in evidence in the Vancouver market.

Kay’s website features a warning not to trust home sales numbers for both Toronto and Vancouver.

“If you need statistics in any of these areas DO NOT rely on the real estate associations serving those communities. You must get audited data for these areas,” the website states.

UPDATE: Caroline Feeley, a sales rep with Sutton Group Quantum Realty in Mississauga, writes in to say she agrees the double and triple listings are distorting the statistics.

"I am not at all pleased with loading a listing three times and I feel that it is ridiculous to have to do so," Feeley writes. But she explains she has no choice, because of the way the "fractured" real estate board system works. In her own words:

What you don't know and what the public doesn't know is that the listing needs to appear separately on the Toronto Real Estate Board, the Oakville, Milton and District Real Estate Board and the Realtor's Association of Hamilton and Burlington for Realtors to be able to search the full listing from their home board. What this means is that if I were to only list the property on RAHB, realtors from the other boards would not be able to search and find the full listing! Since most properties are purchased with a buyer working with a realtor, I will do everything I can to ensure that realtors across the real estate boards have access to all my listing.

My listing in Waterdown should, at the very least, be listed on RAHB because this is where the property is located, and local realtors need to have full access to the listing. But why should Oakville and Mississauga agents not also be able to see this listing on their board? To me, it's ridiculous that they don't automatically have this access. A lot of real estate transactions are from people moving east to west. If my listing on Victoria Street was not also listed on OMDREB and TREB, I would potentially be excluding all the prospective buyers working with realtors on those boards.

As long as we have multiple real estate boards in the province that operate this way, a good realtor will list on multiple boards. I hope that one day soon, there will be an amalgamation of boards or some way that we can ensure all realtors have full access to listings, but until that day, in my practice anyway, the numbers will be distorted as I continue to serve the best interest of my client.

Like this article? Follow our Facebook page

Or follow us on Twitter