To evaluate only one part of that dialogue is always going to be insufficient. There is a need for regular constructive criticism of both clergy and the ministry setting. When evaluations are focused only on the pastor, or done very irregularly, they too often become tools of destructive criticism cloaked in anonymity. Every congregation has basic expectations of its pastor. Some of these expectations can be evaluated with precision.
Some expectations are very subjective.
No one can please everyone. Many people will like sermons that others do not appreciate. Some people want pastoral visits and others do not. Pastors can only visit in the hospital if they are told that people are there. No single instrument can give the kind of helpful feedback that would come from regular and open conversation with the clergy.