It’s also necessary to acknowledge that multiple variables affect crime rates; factors such as economic cycles, substance abuse, the weather, societal influences, changes in legislation, and so on. None of these are directly within the gift of the police to influence. Also, what about where the police cause an increase in reported crime by having the temerity to find someone carrying a weapon? Surely proactive problem-solving should not be discouraged on the basis that finding hitherto unreported criminal offences is incongruous with an over-simplified crime reduction narrative...I would say many of the examples are outcome measures of the system - which is a better measure than is often used.
However, they are often beyond the control of individuals and even police departments overall (many other factors play a part - economic development, social services system, education system...).
Likely more directly relevant the measurement error is often so high that the figures have more to do with measurement than the actual outcome. And when the figures are being used to blame then it dramatically increases the likelihood the figures will be a poor representation of outcomes.
I would rather see more focus on outcome measures. We should also reduce incentives to misreport data (often blame related).
I think the issues you raise about the system being larger than the police can tackle alone should be a reason to INCREASE the view of the SYSTEM. The important system is LARGER than the police department. When we have institutional walls that break up the system we need to find ways to knock down those walls so the system can work together. Granted this seems nearly impossible given how much difficulty we have even just breaking down barriers inside tiny pieces of our organizations.
Nevertheless that is where the focus should be. We shouldn't decide the outcome measures are not fair given where we put organizational barriers. We should decide that we need to realize when we cut funding for x it drives bad results in section a. And when we allow y to retain fitfully outdated management practices that doesn't just impact their ability to succeed it likely creates lots of other problems all over the place.
Related: Be Careful What You Measure - Millennium Development Goals