See here for the Executive Summary of the "Economic Freedom of the World.2012 Annual Report."
Forty-two variables are used in this ranking exercise that cover five areas:
1.Size of government
2.Legal system and property rights
4.Freedom to trade internationally
So why did the US drop further in the rankings?
"During the past decade, the U.S. rating fell nearly a full point on our 0-to-10 point scale, from 8.65 in 2000 to 7.70 in 2010. While it is difficult to pinpoint all the reasons for this decline, the increased use of eminent domain, the ramifications of the wars on terrorism and drugs, and the violation of the property rights of bondholders in the bailout of automobile companies have all clearly weakened private property and the rule of law tradition of the United States."
It is getting worse.From 1980 to 2000 the US trails only Hong Kong and Singapore,by 2005 US fell to
8th and now 18th.
Although I could find no analysis of the role of the Affordable Care Act in their publication, clearly the ACA did not enhance freedom economic or other wise. The regulations ( many of which are still being written) will limit the freedom of all elements of the health care system. The ACA which in this respect has been validated by the Supreme Count,forces individual to purchase a certain product ( health insurance). If that is not the opposite of economic freedom, I don't know what is. If that were factored into the analysis (maybe it was),US would be even lower than 18th.