(REUTERS) - Paul Clement became the sixth Premier League manager sacked this season when bottom club Swansea City ended his one-year tenure on Wednesday (Dec 20) but any upswing in results the Swans enjoy will be largely down to luck, according to a leading analyst.

The so-called "new manager bounce" that often accompanies a club parting ways with a manager and hiring a new one as demonstrated this month with West Ham's resurgence under David Moyes after he replaced Slaven Bilic.

But research by the 21st Club suggests the phenomenon is overrated.

"We have done a lot of research on this. Football is an unusual sport and is quite low scoring. That means a team can play well and lose or play poorly and win," Omar Chaudhuri, head of football intelligence at the London-based sports consultants, told Reuters.

"What we see is that when managers are sacked, a lot of the times their teams have been playing okay but without luck. It only needs one crucial moment per game to go against you, and that is the difference between three points and one or one point and no points.

"In most cases, sacked managers are unlucky.

"It's like calling tails five times in a row in a coin toss and losing each one. The next person calls tails and wins. It's the same with a football manager."

Chaudhuri says 75 per cent of the managerial bounce is down to luck with the other 25 per cent to do with fixtures, players returning from injury and a lift in spirits in dressing room.

He says clubs who stick with a manager through a bad match often find that the bounce effect occurs without any change in the man at the top.

"The best example is (Liverpool manager) Jurgen Klopp in his final season at Dortmund," Chaudhuri said.

"They were bottom in February but because he had a special relationship with the club they did not sack him. In the second half of the season, Dortmund were the second-best team in Germany according to results, and yet the performances were roughly the same. The key thing was their luck changed."

According to statistics compiled by the 21st Club for Europe's five biggest leagues, clubs earned 0.8 points per game in the eight games prior to a managerial sacking, compared to 1.2 points in the subsequent eight.

Yet match statistics, in terms of quality and quantity of chances created and conceded, were virtually identical.

The new manager bounce has certainly had a big impact this season with Crystal Palace, Leicester and Everton, like West Ham, all enjoying an upturn in results since appointing Roy Hodgson, Claude Puel and Sam Allardyce respectively.

West Brom will be hoping for the same having replaced Tony Pulis with Alan Pardew.

Pulis is now a candidate for the Swansea job with Bilic, as the managerial revolving door gathers pace with a cast of familiar faces in the frame for any new vacancy.

"What other kind of business operates like that?" Chaudhuri said.

"A manager is effectively the managing director or chief executive officer (CEO) of the business and in what other industry would you, A, hire a new CEO in the space of two weeks and, B, would the top of your shortlist have people recently sacked for poor results at a rival firm.

"It's totally illogical but football is strange."