The rule of economic integration in congregational life can be seen in the missionary outreach of the major denominations. There is much talk in theological circles about the ``Church as Mission'' and the ``Church's Mission''; theologians have been stressing the fact that the Church does not exist for its own sake but as a testimony in the world for the healing of the world. A crucial question, therefore, is what evangelism and mission actually mean in metropolitan Protestantism. If economic integration really shapes congregational life, then evangelism should be a process of extending economic integration. The task of a congregation would be defined, according to economic integration, as the work of co-opting individuals and families of similar social and economic position to replenish the nuclear core of the congregation. (Co-optation means to choose by joint action in order to fill a vacancy; it can also mean the assimilation of centers of power from an environment in order to strengthen an organization.) In a mobile society, congregational health depends on a constant process of recruitment; this recruitment, however, must follow the pattern of economic integration or it will disrupt the congregation; therefore, the recruitment or missionary outreach of the congregation will be co-optation rather than proclamation -- like elements will have to be assimilated.

Evangelism and congregational outreach have not been carefully studied in the churches; one study in Pittsburgh, however, has illuminated the situation. In a sample of new members of Pittsburgh churches, almost 60 per cent were recruited by initial ``contacts with friendly members.'' If we add to these contacts with friendly members the ``contacts with an organization of the church'' (11.2 per cent of the cases), then a substantial two thirds of all recruitment is through friendly contact. On the surface, this seems a sound approach to Christian mission: members of the congregation show by their friendly attitudes that they care for new people; the new people respond in kind by joining the church.