Is there an epidemic of school shootings? Parents are understandably fearful, but their fear is unjustified. Schools are relatively safe places, and they have gotten much safer.

While even one death is too many, the number of children killed in school shootings has declined over the last couple of decades. The drop is even larger than the overall decline in the murder rate.

Last week, Michael Bloomberg’s various gun control organizations exacerbated the fears by claiming that there were 74 school shootings since the actual Newtown school shooting in December 2012, and that something must be done. But Bloomberg’s numbers were dead wrong. They inflated the number by including attacks that were off of school property and unrelated to the school, lone suicides well after school hours by adults, a justifiable defensive use of a gun and gang fights outside of school hours.

[pullquote]

Last week, CNN investigated Bloomberg’s claim and said that over the previous 18 months, there had been 15 incidents where guns were brought onto school grounds in attempts to harm people.

But that is still a large number. A better measure is to focus on the amount of harm – the number of people killed – rather than the number of attacks.

On that front, things have improved dramatically over the last couple of decades. During the 2013-14 school year, there were three non-gang, non-suicide killings at universities, and three more at K-12 schools.

The National School Safety Center, a good source of statistics, started collecting data on K-12 violence in the 1992-93 school year. During the first five years, from 1992-93 to 1996-97, there were 26.8 gun murders per year on K-12 and university school property. In contrast, during the last five school years, 2009-10 to 2013-14, the average was 12 – a 55 percent drop.

There have obviously been ups and downs from year to year since large school shootings are rare, but the five-year averages have shown a consistent drop in gun deaths. Even including the Sandy Hook Elementary School massacre, that is the trend.

With 77 million Americans between the ages of 5 and 22, that implies a school murder rate of 0.008 per 100,000 people in the 2013-14 school year, well less than 1 percent of the overall murder rate.

But mass school shootings aren’t the only thing where reality differs from people’s perceptions. Overall, firearm homicide rates have plummeted as much as the firearm murders at school since 1992 (a 52 percent drop by 2012), but a recent Pew poll shows 45 percent of Americans believe that firearm homicide rates have gone up, only 10 percent realized that the rate had actually gone down.

The same misperception is happening on mass school shootings.

The media shapes our views on guns and crime in other ways. What the media deems “newsworthy” doesn’t always give Americans an accurate measure of what is happening. Take the case of defensive gun uses. When was the last time you watched the national news and saw a story about someone using their gun to save a life? Yet, the national news ignores stories of guns being used to save lives, but the best estimates from survey data indicate that defensive gun uses are about four to five times more common than crimes committed with guns.

Of course, the media’s understandable obsession with newsworthiness not only gives Americans a misimpression of what is happening to crime rates and mass killings, but it also encourages mass killers, who thrive on this attention. Reading the Santa Barbara killer’s manifesto, it is clear that he was just one more person who craved attention and felt he could get it by killing as many people as possible.

Unfortunately, these misimpressions caused by the media have real consequences. Legislation gets passed that disarms law-abiding citizens and makes attacks more likely.