Many pastors I have known measure the effectiveness of their preaching by the numbers who “come forward.” I am not necessarily or even primarily thinking about salvation, just in general. Although it certainly could apply to salvation. And yet, the way to measure the effectiveness of a word given, if it is given by the power of the Holy Spirit, is the change that it effects in the hearer. Fruits of repentance are the measure.
If repentance is changing one’s mind that leads to a change of one’s actions, and it is, then change would be the flesh on the bone of genuine repentance. If Christendom needs to repent, and it does, then change would be the measure of it. To simply say the words or acknowledge the need and continue on the way it has always been is a sure sign that… these people come near to God with their mouths and honor me with their lips but they remove their hearts far from Me, And their reverence for Me consists of tradition learned by rote.( Isa 29:13)
If a man is satisfied with giving the Word and having people come forward for repentance, but does not agonize over a lack of any change, then he is merely perpetuating the traditions of men that they have learned by rote and in fact is a contributor to the very tradition they claim not to be a part of.
A Call To The Remnant 