TIFs are an economic development tool that basically subsidizes development based on future gain from increased land values, and often used to improve blighted neighborhoods. The Cato report argues that TIFs do not increase economic development.
Randal O'Toole wrote the report, and summarizes the results:
"At best, it [TIFs] moves development that would have taken place somewhere else in a community to the TIF district. That means it generates no net tax revenues, so the TIF district effectively takes taxes from schools and other tax entities."