Evaluate the effectiveness of direct democracy?
This is largely a matter of opinion. There is no question that direct democracy is less efficient than representative democracy. But there is a great deal of dispute over whether direct democracy is good in cases where it is feasible.
A major example of this is in the intiative and referendum procedures that we have here in the Western US. By using these mechanisms, individual citizens are able to vote directly on issues that are set before them. This is quite controversial.
Supporters of such direct democracy argue that this gives the people a more direct voice and that this is good for a democracy. Detractors argue that the people do not have the time or energy to properly inform themselves on complicated issues like taxation (a big issue in many initiatives). They believe that direct democracy leads to bad decisions.
Direct democracy gives people more power to express their opinion in framing of laws that affect them as they vote for or against them directly. This is a more effective way than citizens having to go through their elected representatives. It has been found that people, who do not cast their vote for the election of candidates representing them, actively participate in processes of direct democracy.
But direct democracy has its drawbacks too. It has been found to have been used many times for personal gains by corporations and individuals. There are many cases where people were paid either to get the initiative passed or to cast their votes during the actual voting process. It also allows people to find a way around the normal checks and balances that come when these things are done through governments and legislative bodies.