Your high school guidance counselor should have steered you away from these three career paths: hand grenade tester, freezer salesman in Siberia and head coach of just about any sport. The longevity and success potential of each is limited.

Just halfway through the current 16-game NFL season, three coaches, Lane Kiffin (Oakland Raiders), Scott Linehan (St. Louis Rams) and Mike Nolan (San Francisco 49ers), have been asked to "pursue other opportunities."

Add to that two NHL coaches, Denis Savard (Chicago Blackhawks), who only made it to the fourth game of this year's 82-game schedule and now Barry Melrose, who was just fired after only 16 games. On the other end of the season, Ned Yost (Milwaukee Brewers), led his baseball team through 150 regular season games only to be fired with 12 games left in the season, even though the Brewers were still battling for a playoff spot.

Of course, we all should be so lucky to be bought out of our multi-million dollar contracts, so that we could contemplate our vocational options from a Caribbean beach. But do all of these pink slips and "interim" coaches help a team?

Since 1970, no NFL head coach hired in midseason has even made it to the playoffs, never mind the Super Bowl. And, while the Brewers did make the postseason this year, their record was only 7-5 in those last 12 games and then they lost in the divisional series, four games to one.

Yet team owners continue to panic and react rather than stick with the coach that, at one time, they felt was the man for the job. On the off chance that these owners enjoy reading academic research papers, two recent studies could confirm for them that reaching for the hook during midseason is not supported by results.

Economics professors from the Universita della Calabria, Maria De Paola and Vincenzo Scoppa, looked at the top Italian soccer league, Serie A, over five seasons from 2003-04 to 2007-08. Serie A is one of the most well-known leagues in the world, and an average of 41 percent of its 20 teams changed coaches during any given year in this five-year dataset. The researchers measured team performance before and after each of the 40 changes, using team points (3 for a win, 1 for a tie, and 0 for a loss), goals scored, goals against and their difference, known as goal differential.  The results showed no statistically significant improvements in team performance.

For several reasons that De Paola and Scoppa point out, this makes logical sense. So much of a team's success is determined when they first step on the field at the beginning of the season. The quality of the players on the roster, the tactical system that is in place and the influence of the fans and local media are variables that a new coach may not able to affect.

The game schedule can also play a role. If a team faces a string of tough opponents early in the season, the old coach may be unfairly compared to the new coach who has an easier schedule after the change. Also, over the course of a season, each team's record will statistically gather around its expected performance level. Since most coaching changes are made after a run of poor results, the new coach may benefit from a simple "regression to the mean" by enjoying a string of good results that may have nothing to do with the coach.

Change the sport and the league and the results are still the same. Three researchers led by Leif Arnesson at Mid Sweden University collected data from 30 years of the Elitserien or Swedish Elite League, the NHL of Sweden, to measure the impact of changing head coaches midseason.

"The results of our study indicate rather clearly that it was a mistake to replace the coach in all of these cases," says Arnesson. "If you're thinking about getting a new coach, you should at least avoid making your move while the season is under way. A word of advice to those who are in charge of recruiting coaches is therefore: 'Don't replace the coach, at any rate if you have a good coach, if you're in the middle of the season, or if the team is in trouble."

While the old saying, "you can't fire all the players so you might as well fire the coach", seems like the quick fix to a underperforming season, owners and fans should probably be patient.  At the end of the season, however, its a "whole new ball game" so we can "get 'em next year"!

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