Most of us take for granted that money spent on education is well spent money. Unfortunately, the data doesn't support that generalization. Many studies have come to that conclusion. I'd urge you to take a look at a very good analysis done by The Heritage Foundation [full analysis] that looks at spending and results and then makes some recommendations. [click image for larger view]
There are a variety of factors affecting school district performance. Other charts are available in that analysis begin to address those factors. Here in Michigan, it was obvious long before this study was published that the Detroit Public Schools system is without peer when it comes to failure. Is it the money? No. Is it the teachers? Somewhat. Is it the system? Definitely.
I'll include the students and families of those students as part of the definition of "the system." You get the leaders for whom you vote. Detroiters kept voting for leaders that make Detroit #1... in failure. Will it change soon. Not if Detroit's City Council has its way.