We'd like to have one person in each town take responsibility for the list of congregations in that town. We don't anticipate we'll ever have a perfectly complete list for any town, but some local person is better able to discover existing lists (Chamber of Commerce, telephone book, etc.) and to integrate existing lists adding critical information whenever we need it. The list for each town will become as good as the local person cares to make it.
To get started, the "lead person" could simply print out the page for his or her town and mark all congregations that seem to appear twice. If address is same, that is sufficient to establish that the listings are redundant, but if there is inconsistent data it should get resolved in a reasonable manner, probably with a phone call. For now, corrections can be written onto the page for that town and sent to the database manager. Soon we'll have a relational database and a means whereby corrections can be made directly on one's computer.