Knowing how you’re successful is vital to your ministry.  But you don’t want to just collect all that data and sit on it.  You’ll be like the foolish man in the Parable of the Talents.  He kept his master’s money and buried it.  The Master was furious and took it away.  If you don’t talk about how your successful, people will draw their own conclusions.  Unfortunately, they may assume you’re doing a horrible job.  No one wants that.