Use your mission statement until people get sick of it. We use the mission statement with newcomers and have lay people tell their stories. This way the new people learn our purpose as a congregation and get an introduction to our style of openness. Use it for evaluations. Look at your budget and time spent.
Some congregations go crazy in evaluations.
An evaluation can be done lightly, as you occasionally look at a map. I think it's very important to evaluate small groups and committees. This helps the members to be more responsible. I am finding that an extended check-in, sharing where we think God is acting in our lives and in our life together, helps speed up the business part. A congregation-wide approach of spirituality for a season will encourage individuals to awaken and will probably change the nature of your congregation.