No, I don't have one or know where one is, but such an index would be useful to voters and policymakers around the world. The tragedy is not when these innovations are attempted, and fail; the tragedy is where they are tried, and work, but no one knows about it, and so we think all these questions are mere political theory when in fact we have cold hard practical data.
- For example, who knew (at least in the U.S. where I'm writing) that in 2001 Portugal decriminalized all drugs? In 2001. Suddenly California's November vote to legalize marijuana no longer seems so cutting edge.
- For another example, Uruguay is experimenting with competing simultaneous currencies. At the very least it will be interesting to see if a gold-standard currency re-emerges out of such a system. (I predict not; more on the the coincidental nature of the gold standard here.)
One innovation that has yet to be institutionalized is the adoption of automatically-assigned publicly accountable metrics on public programs; it continues to amaze that democratic publics are so willing to let their leaders avoid closing the loop. What democracies typically rely on are journalists, but in an increasingly complex age I don't think this assumption will hold much longer. One exception is civil engineering projects, which in some areas of the U.S. do publish goals and progress, but local governments don't often trumpet their successes and failures. For example: if a freeway ramp goes up ahead of schedule and under budget? Great! The civil engineering firm should become a local household hero! That's a real example, except unfortunately for the household hero part. When this happened with construction on a feeder ramp to the San Francisco Bay Bridge in 2007, no one seemed to notice or care, despite that hundreds of thousands used the freeway every day and it had a direct impact on the local economy and quality of life.
On the other hand, in the democratic feedback loop world I'm envisioning, what if some measure - educational, environmental, economic growth promotion, etc. - did not hit the targets it claimed it would? An informed public would demand that their representatives fix it or throw it out. A much stronger version of this system is futarchy, proposed by Robin Hanson; in such a system, not only do you mandatorily attach metrics to new law and policy, you adjust how much each voter's voice counts based on how well the candidates and policies s/he has voted for achieve their goals. If you keep voting for measures and candidates that say they'll achieve X, but don't, you keep losing clout. If this seems undemocratic, recognize that we already partly do it, although clumsily and with proxy indicators; felons and some mentally disable people aren't allowed to vote in the United States.
Not only would clearer public accountability (clearer by virtue of objective metrics) orient voters and officials more heavily toward results, it would give good-faith minority opposition leaders some concrete grounds on which to base objections (see Megan McArdle's request to build metrics into the healthcare reform package that just passed the U.S. Congress.) Your party thinks that law X won't achieve outcome Y? Fine. Let's all bet on it. Legitimate objections to majority policy are realized when Y doesn't happen, and bad faith negotiators who don't have a real objections (or don't have one that the voting public supports) now have a more difficult job.
In any event, the outcomes of others' experiments are worth watching. Decisions involving millions of people are obviously important, and it would be great for a political science department somewhere to put together a one-stop shop for such innovations - along with, of course, objective results.