City properties (crime, etc) change rate

Long time lurker, love the mod. Having trouble with one thing and have been unable to find an answer through searching. In the properties tab of a city screen, it shows the current level of the Crime, education, disease, etc. I believe the parentheses are supposed to be the change per turn, but the numbers and the scroll over text doesn't seem to add up.

For example, in my current game, crime shows the following:

"Constant building sources: -21/turn
General property sources (population, decay): +20 per turn
However, the crime change is at (+0)

Disease is:

"Constant building sources: -2/turn
General property sources (population, decay): +9 per turn
However, the change is at (-2)

What is going on with this? Can someone explain or point me to an explanation of what I am missing? It really makes it difficult to plan my city to avoid the negative impacts of these things.

Thanks in advance!

Welcome to C2C.

You can't figure out Crime from the City screen numbers. It's more like a barometer. Keep adding Anti crime Bldgs and/or units till you see movement. It's not simple addition or subtraction. Same for Disease.

JosEPh

For those looking for a mathematical breakdown of how the system works, this thread does its best at least.

That link doesn't work, Thunderbrd.