Implementing a graduated real estate transfer tax as a source of new revenue has some advantages, but it is also extremely volatile. There has not been sufficient evaluation of the proposed graduated tax’s potential impact on the City’s real estate market and economy or a public explanation as to how the changes to the tax would impact tax burden by location and property use type. The CF analysis of Illinois Dept. of Revenue transfer tax data reached several findings that can be read in the full report. The Suntimes summed up the RETT study- "Civic Federation questions volatility, structure, fairness" of the real estate transfer tax.
This is a good read and the first important study about the potential impact of the RETT on property tax assessments.