Many congregations are not genuinely open to new people. They think they are, but they are not. This is obvious quickly to guests/visitors. Therefore, to find out if your congregation expresses positive openness ask the people who are nearly attending your congregation.
Congregations needing to transform must be positively assertive in welcoming new people into the congregation. It must be obvious that new people are wanted, and that there is a place for them. Their ideas and perspective must be respected. The culture, fellowship, and relationships within the congregation must be open to letting new people in.