This past summer, two men sexually assaulted seven women in and around the U-M campus. A rash of burglaries last year enraged folks on the near northwest side. And just a few weeks ago, a thief or thieves broke into four cars in Gallup Park and stole three purses, two cell phones, an iPad, and physical therapy equipment–and what kind of depraved person steals physical therapy equipment?

Given those terrible crimes and all the others reported every day by the national, state, and local media, it’s hard to believe that crime in Ann Arbor has dropped like a rock over the last twenty-five years. But the numbers don’t lie. In the four major categories tracked on the Ann Arbor Observer’s monthly Crime Map–robbery, sexual assault, vehicle theft, and burglary–the number of crimes reported has fallen by an amazing 70 percent, from 2,670 in 1986 to 790 in 2010.

Robbery, sexual assault, and vehicle theft are rare enough that rates sometimes fluctuate by 30 percent or more from year to year. To iron out those oscillations, we compared rates for individual crimes based on five-year averages–1986-1990 vs. 2006-2010.

Between those two periods, violent crime was cut in half: robbery fell 52 percent, from an average 157 to seventy-five per year, and sexual assault 51 percent, from an average 131 to sixty-four per year. Property crime dropped even more: burglary by 63 percent, from an average 1,647 to 605 per year, and vehicle theft by an astounding 71 percent, from an average 526 to 155 per year–much of that due to better car lock systems.

Mayor John Hieftje and police chief Barnett Jones knew crime had dropped over the last decade, because the AAPD’s analysis unit keeps them well apprised of recent crime trends. But Jones is stunned by the size of the longer-term pattern documented in the Observer’s crime maps and checked against FBI and Michigan State Police statistics.

“Your numbers are … wow,” says Jones.

Hieftje says he isn’t surprised by the decline, but he admits, “nobody’s ever seen crime down like this–I’ve never seen numbers like this.”

“Wow!” exclaims Greg O’Dell, unconsciously echoing Jones, his former boss. Currently chief of the U-M Department of Public Safety, O’Dell was deputy chief of the AAPD before that. “I would never have guessed. Those numbers are wonderful!”

Ingrid Sheldon, mayor from 1993 through 2000, pauses before saying, “that’s pretty impressive.”

“Amazing,” says Carl Ent, Ann Arbor’s police chief from 1995 through 2000. “That’s staggering. Does that mean we’re all becoming better people?”

That’s actually one theory. But there have been other, more tangible factors at work. Because crime hasn’t fallen all at once and it hasn’t fallen steadily. It fell in three distinct waves–and the first decline was the steepest.

In the first nine years, the number of robberies, sexual assaults, burglaries, and vehicle thefts tracked on the Crime Map dropped straight down–from 2,670 in 1986 to 1,416 in 1994. This decline wasn’t unique to Ann Arbor: crime across the state dropped in the same four categories, though not as much. While Michigan’s total crime rate fell 32 percent, ours dropped by 47 percent.

The most likely reason for the decline can be summed up in a single word: jail. More arrests, longer sentences, fewer paroles, and a prison-building spree between 1986 and 1996 almost tripled Michigan’s prisoner population, from 15,000 to 42,000. The best evidence that increased incarceration worked in Michigan is that the national crime rate kept right on climbing until 1993–then began dropping when the whole nation went on a prison-building spree.

“Most police wouldn’t say this, but there needs to be enough prisons for the people who need to be there,” says former AAPD chief Carl Ent. “It’s the ‘hot stove’ theory: if you touch it, you’re going to get burned.” Ent knows from experience that increased incarceration works. “When the sheriff’s department’s jail was packed, they’d have to release prisoners back into the community, and when they did, the crime rate always went up.”

“It makes sense,” Greg O’Dell agrees. “If you lock up career criminals you’ll reduce crime, because a large fraction of crimes are committed by a small fraction of the criminals.”

The second decline was less steady but still unmistakable. Though violent crimes fell again in 1995, property crimes rose and took the total in all four categories up to 1,567 in 1996. But thereafter, the downward trend resumed; despite one more upward bump, in 2002, the total fell to 1,066 by 2004–another 32 percent drop in eight years.

Again, increased incarceration may have helped. As Michigan’s prison population rose from 42,000 in 1996 to 51,000 in 2006, the state’s crime rate dropped with it, though again not nearly as far as it did in Ann Arbor. But the city’s mayor and police chief through much of the ’90s credit most of the decline to community policing–getting cops out of their cars and stations and onto the street. “Those were the good years,” remembers Ingrid Sheldon. “Because of increased property values, we had an increased police presence, and because of grants from the feds, we were able to add bike patrols, beat patrols, and community policing.”

Expanding community policing was Carl Ent’s charge when he was hired in 1995. “The mentality used to be ‘you call, we haul,'” explains Ent, now a vice president at the Bank of Ann Arbor. “In other words, we got called and we responded by showing up, almost always after the crime was committed. Community policing … put officers out in the neighborhoods where they got to know people. Once that started, crime went up because there were more reports of crimes–and then it went down, because the number of people who commit crimes are few in number, and if you put them away, you can really make a dent in crime.”

As Sheldon notes, there were also more cops in town–and not just AAPD officers. The university started its own police force in 1990 with eight officers, and the number rose to about fifty-four by the end of the decade. With the AAPD’s 200, that meant in the year 2000, 254 cops were patrolling the city and the campus.

The U-M officers helped make the ’90s a golden age for law enforcement. “Having a whole new police force in town permitted us to look at ways to enhance downtown and take care of other things that needed taking care of,” says Sheldon. “Gang violence disappeared, and so did most of the graffiti. Policing in low-income housing got tougher. And on campus, property crimes went down because of the new police force.”

Not everything was golden in the ’90s. “We had two serial rapists,” Greg O’Dell remembers. “Both were eventually caught. One person makes a huge difference in total number of crimes in some categories.”

“Large numbers of burglaries and rapes are committed by one person,” confirms Carl Ent, “and once he’s caught, the number goes back down. But because the numbers are so small, it has a big impact on the rates.”

It certainly does. When the serial rapists were at large in 1992-93 and 1996-97, sexual assaults jumped 35 and 27 percent from the year before. That sounds enormous, but the actual numbers were from 97 to 131 and from 99 to 126–with much of the differences attributable to single individuals.

“If you look at the percentages in some categories, some people see a dramatic trend,” says O’Dell. “And sometimes there isn’t one.”

The third and most recent decline was the second steepest and the least explicable. In 2005, increases in all four categories bumped the total number of crimes reported on the Observer maps up to 1,293. Then the count fell for five years straight, hitting a new low of 790 in 2010. Last year the city and U-M forces recorded 39 percent fewer crimes than they had five years earlier, and 70 percent fewer than the AAPD alone handled in 1986. The biggest reductions were in burglaries, from a high of 1,791 in 1987 to 524, and in vehicle thefts, which peaked at 647 in 1986 and dwindled to 130 in 2010.

Increased incarceration can’t explain the latest drop, since Michigan’s prison population fell during the last five years.Even more confounding, crime continued to shrink right through the biggest economic crisis of the postwar era, which drove the local unemployment rate to 8.6 percent last year–upending the old law enforcement adage that more unemployment means more crime.

U-M police chief O’Dell offers another explanation: “It’s because of the decline of young people. We have some crime from people in their fifties and sixties, but very little compared with the number of crimes committed by people in their teens and early twenties. A large number of crimes are crazy impulse crimes fueled by drugs and alcohol, and younger people have more trouble with alcohol and drugs.”

It’s true that the rest of Michigan has grown grayer over the last decade. But that doesn’t appear to be the case in Ann Arbor. Since 1986, the public-school headcount has increased by about 15 percent, and U-M enrollment is at an all-time high.

Jones believes more advanced technology has played a part. “Citizens have cell phones with cameras, plus we have surveillance cameras around town now, and it’s helped us in a number of cases. Of course, this community doesn’t want them. But we don’t want to monitor them–we don’t have the manpower to do it even if we wanted to!–we only look at them after the crime has been committed.”

Catching more criminals surely played a part. “We’d never had a serial rapist in town since I’d been here until last summer,” says Jones, who was hired in 2006. “Before this year, we had random occurrences, mostly people who knew each other, never guys running around groping women. One guy we caught. The other one we’re still looking for–but we’ll get him. It’s personal for me. He did this in my community.”

The AAPD also got the northwest burglar. “That neighborhood was enraged and rightly so,” remembers Jones. “We knew about it. We knew we had somebody out there who didn’t belong. Turned out it was a young man who’d moved in and thought he’d found a great new fishing hole. We caught the people around him, the people who were buying and selling the stuff he stole, and then we caught him.”

What about Carl Ent’s question? Is it possible that fewer people today are criminally inclined–that people really are getting nicer?

“There is less violence in the world for sure,” says Hieftje. “I read about it in the New York Times. So people may indeed be becoming nicer.” Hieftje is referring to Steven Pinker’s The Better Angels of our Nature, which demonstrates over 700 pages that human violence has declined enormously over the past 10,000 years and that humanity is currently enjoying the safest times in history.

Hieftje can point to local examples. “There’re no more sports riots on South U”–though, admittedly, U-M fans have lately had less to celebrate. “There’re fewer and less often fatal fights outside nightclubs. Assaults are down this year, and last year, twenty assaults alone can be attributed to one place: the Dream Night Club.”

Carl Ent thinks it’s possible people are getting nicer. “People want to be nice. It’s just a lot easier. But I don’t have a tragic view of human nature–I think times change, and so do people.”

The current chief doesn’t share his predecessor’s optimism. “Human beings have a sinful nature,” says Jones, who’s a Pentecostal preacher as well as a cop. “I’d love to believe [the reduction in crime] is because goodness has triumphed over evil, like I’d love for the crime rate to be zero. But I don’t think it will ever happen, and I have to be ready for the next new crime. It’s my job to be a pessimist.”

Even with less crime, no past or present mayor or police chief says Ann Arbor should have fewer cops. Right now, the AAPD has 118 officers and the U-M DPS has fifty-four, for a total of 172. That’s 32 percent fewer than ten years ago–but, then, crime is down 38 percent for the same period.

“We need more cops,” insists Jones. “My job is public welfare and community safety, and I require bodies to secure the city and officers’ safety. I’ve thought long and hard about it, and I think a reasonable number is 150. With that many, I’d have ten to fifteen cars out on every shift, I’d have a fugitive apprehension team, I’d have a narcotics unit, and I’d beat the hell out of those numbers!”

There’s little doubt that he would, but increasing the number of cops isn’t likely in the current economy. However, after shrinking the AAPD by 41 percent over the last decade, Hieftje says he doesn’t want to shrink it any further. “Our budget next year calls for 10 to 12 percent reductions in almost every department, but I want no further reductions in the police department. In fact, we have a new contract now, so we’ll be able to hire back the four officers we laid off in July.” (See UpFront, p. 9.) What would he like Chief Jones to do with them? “I’d like to see more officers downtown,” the mayor replies.

“Should we lower staffing levels?” O’Dell asks rhetorically. “It depends on what other activities the police engage in,” he answers. “There’s very little crime at football games, but you still need staff to direct traffic and do crowd control. There’s a lot more to policing than the crime numbers.”

According to the Crime Map data, the four categories tracked have fallen another 13 percent in the first nine months of 2011. But despite those long- and short-term trends, both Hieftje and Jones think the crime rate is likely go back up in the future.

“We are having an exceptional year this year, so it’s almost bound to go up next year,” says Hieftje.

“It’s got to because it’s down so low,” affirms Jones. “Next year may be normal, which will be up.”

Perhaps. But the new Ann Arbor is still far more peaceful than the old one. Neither the mayor nor the police chief expects crime to return to the levels of the 1980s. That may be the surest sign of the city’s transformation: crime rates that were “normal” twenty-five years ago would seem today like a terrible assault.