To me it is not so much about quantifying the effectiveness as it is about qualifying the results. This is not a trivial question as democracy, which is in essence a non-violent system for transition of power, relies on a nearly unanimous acceptance of the process and the results.

So, for introspection, and I know it is not a perfect analogy, but imagine you are at a scientific presentation, and you're gut feeling tells you there is a flaw in the arguments presented. So you pose a question but instead of receiving an answer that might lay to rest your misgivings, the speaker just says "That question is not allowed. Next.". How likely is it that that response changed your mind in favor of the theories presented?