When it comes to high school sports, the playing field is supposed to be an extension of the classroom. If so, too many coaches and parents are teaching the wrong lessons.

The number of game officials has dropped significantly in almost every sport over the last decade – and the main reason is constant abuse from the sidelines and the stands.

In Maine, the number of basketball referees is down 13 percent in the last decade. For soccer, it’s 9 percent, and for baseball, 25 percent. In field hockey, the playoff schedule had to be redrawn because there were not enough officials to hold quarterfinal games on the same day.

It’s not just Maine. In Michigan, the number of officials across all sports fell 23 percent in a decade. Oregon lost 12 percent in three years. In Ohio, the number of baseball officials declined 18 percent in seven years, while football lost 11 percent. Southern California, New York state and Nevada are among the other areas that have reported declines in the number of scholastic game officials.

And this is all taking place as the number of high school athletes rises steadily.

Low pay is a factor, as is the low unemployment rate, which has made it easier to find second jobs other than officiating. In many cases, too, people can’t fit officiating into their busy lives, including work and longer commutes.

But it is the hectoring and hollering that is causing most officials to hang up the whistle and pinstripes.

In 2017, the National Association of Sports Officials reached out to its members, hoping to get 500 respondents to a survey. The organization found its members ready to talk about a worsening situation – 17,000 officials from across the country ended up answering the organization’s questions.

More than 70 percent said coaches treat officials unfairly, while nearly 85 percent said spectators do. Forty-seven percent said they had felt unsafe during a game.

Only 30 percent of officials make it past their third year, and 75 percent of those who quit say “adult behavior” was the deciding factor.

The problem isn’t critical yet, but it is beginning to disrupt scheduling. And it will get worse if something isn’t done to replace the older generation of officials – in Maine, for instance, there are 35 high school softball umpires over the age of 70 but only 22 younger than 40.

More troubling than the loss of a few officials, however, is the message that is being sent to the students for whom sports is supposed impart the positive lessons of sacrifice, hard work and sportsmanship.

By acting out toward officials, parents are telling their children that a $5 ticket buys them the right to harass, humiliate and disparage another person, and that the $75 the official earns means he or she has to take it.

In a heated high school game, it seems the only thing both sides can agree on is that the referee stinks. Officials walk into that environment on a nightly basis, and they do their job well despite the unreasonable, embarrassing attacks on them.

It’s behavior that would never be tolerated in a classroom, and it shouldn’t be tolerated in the gym or on the field, either.