Pocket-book issues may have trumped voters' other concerns in the Scarborough-Rouge River byelection Thursday night — pushing the Progressive Conservatives to victory, even though party leader Patrick Brown did an about-face on the divisive sex-ed file, experts say.

On Thursday, the Liberals lost their 18-year hold on the riding, losing the seat to PC candidate Raymond Cho by a decisive margin.

But the historic result may have surprised no one more than Brown himself, who acknowledged ahead of the byelection, that his changing position on the Liberal government's sex-ed curriculum could cost the party.

Brown promised in a letter last week to scrap the curriculum; a position he called a "mistake" on Monday.

But a Ryerson political science professor says just taking a stand on the contentious file may have been enough to solidify the party's win, notwithstanding the flip-flop.

Existence of letter 'vote-positive' for Brown

"The sheer existence of that letter was vote-positive for Mr. Brown," Myer Siemiatycki told CBC News Friday..

"That letter was distributed widely in that constituency… Even though there was a retraction, the people who got the message at the door may not have followed subsequent media coverage or they may or may not know about the retraction."

Ahead of Brown's reversal on Monday, Cho maintained the sex-ed issue was indeed one that people in his riding were passionate about.

"When I look at my riding, the huge majority of Muslim, Catholic, Hindu, Chinese," he said. "All these parents are quite concerned about this issue."

Discontent with hydro rates

But Nancy Jin, a local resident and editor of the Chinese-language newspaper Chinese News, suggests the sex-ed issue itself may have had little to do with Cho's success. Jin said the deciding factors instead came down to voters' growing dissatisfaction with the Liberals' position on bottom-line issues.

"I think his winning represents the community's discontent with many issues," including what she calls overspending and mismanagement taxpayers money.

"I think a lots of people changed their vote to the PCs," Jin said. "The consumers have to spend on hydro bills, the rate increase year over year and they are very unhappy with those issues."

It was an issue not lost on Ontario Premier Kathleen Wynne, who following the loss, issued a statement directly addressing the hydro concerns.

Siemiatycki says the low voter turnout in Thursday's byelection and others isn't enough to serve as an indicator that there's a "blue wave" the PCs can ride to a provincial election win in 2018.

But he does say the Liberals will have to pause and reflect on how pocket-book issues, and hydro rates in particular, will affect their chances.

"They will undoubtedly go to the issues of hydro rates, which have been rising significantly and have been generating public pushback," he said. "I think that is one issue that can play and have legs across the province as a whole."