Before I can call upon Christ as my Savior, I have to understand that I need a savior. I have to understand that I am a sinner. I have to have some understanding of what sin is.I have to understand that God exists. I have to understand that I am estranged from that God, and that I am exposed to that God's judgment. I don't reach out for a savior unless I am first convinced that I need a savior. All of that is pre-evangelism. It is involved in the data or the information that a person has to process with his mind before he can either respond to it in faith or reject it in unbelief.