Why Is It Difficult to Measure the Effectiveness of Community

Why is it difficult to measure the effectiveness of community interventions?

A) hard evidence such as frequency of participation in activities do not portray the real impact of the intervention
B) interventions are diverse and therefore it is very difficult to quantify the results
C) communities feel defensive when evaluation of interventions occur
D) there are no objective measurement tools available for community work
E) subjective data is not acceptable as a measure of effectiveness of community interventions