The CPD's ability to react to data like this is severely hampered by the public employee union that is the real governance for the force.
No matter how I look at it, I can't see any net good for voters when public employees unionize. Public employees are meant to serve the community they are employed in. The benefits of taking a government job are supposed to be in that you have a direct result in helping the communities around you; instead, the benefits most people see in government jobs are fat pensions and a bureaucracy that, if you're clever enough, you can get lost enough in to where you don't actually need to work to get paid. If anything ever hits the fan, you have multimillion-dollar, politically-connected attorneys ready to serve you.
In the case of police unions, it strengthens the "thin blue line" into a powerful bureaucracy that only looks out for the interests of its members, very often to the detriment of the people these public servants are supposed to be serving (and always in cases such as we've seen in Chicagoland recently.)
I would love counterexamples to this thought. I can't seem to find any of recent noteworthiness, but that could be due to the current anti-law-enforcement/anti-government streak getting pageviews in the news these days.
Two other non-union teaching gigs are preschool and college, and in both of those areas, the age distribution of teachers drops off precipitously at around 25 for preschool and 35 for college. My interpretation is that teaching has ceased to be a career. Disclaimer: I taught an engineering course at the nearby Big Ten university, but with no intention of doing it for more than one semester.
The teachers union doubtlessly protected the bad apples, but it also protected the good apples from things like wage erosion, gradually increasing workload, and getting blamed for outcomes that they can't control.
And I'm sure that education is in need of massive reform, but any reform will now have to be done with nobody interested in becoming a teacher.
I think that an unusual problem for public sector employees is that their wages are public knowledge, and as a result, are a target of resentment.
Going forward, I expect to see more of a relationship between pay and skill. As I said, the best teachers are the ones who are leaving.
Granted, I'm not wholeheartedly pro union, but I see some areas where unions have served a vital role with no obvious replacement. One is to function as a labor movement in general. The unions weren't perfect at it, but as the unions have been effectively defeated, nobody else has stepped up to speak for workers.
The other has been to make certain occupations -- such as teaching -- worth the risk of pursuing as a career, by providing a trustworthy career roadmap. Other countries provide such a roadmap through government oversight of education -- perhaps the state functions as a union in countries with more pro-labor governments. But our governments haven't stepped up to serve that role. Again, the teachers union wasn't perfect (most teachers believed that it needed to be reformed), but nobody has figured out an alternative way to make teaching career-worthy, or how to make schools work if teaching ceases to be a career.
The problem is that the police's advocate is so much more powerful than its opponents. An adversarial legal system like ours breaks down when the adversaries aren't close to evenly matched.
The benefit goes to the workers (not the voters, except inasmuch as the workers form a moderately large part of the voting public). The private sector consists of many organisations, while in the public sector there's basically a single employer and the employees NEED to unionise to bring about a balance with the powers of the employer.
Put it another way: imagine someone saying "I can't see any net good for voters when public employees aren't indentured slaves". Sure, the voters would get better value from public servants who didn't get paid and could be whipped into working faster, but that's not how we want to run society.
It can be incredibly frustrating to see unions fighting against progress and protecting their own against reasonable discipline. I'm not some union advocate (I'm a non-unionised private sector worker) - it would be great if members could take a more temperate line and bring their unions to a more reasonable position. But what the unions ARE isn't necessarily about bringing about ideal outcomes, it's about sheer exercise of power to fight the corner of their members.
The argument in favour of their existence is that it wouldn't be reasonable to prevent them, risking exposing their members to exploiting by power in the opposite direction.