In using the index it is important to note the following. It is an index of Congregational ministers. Because many congregations that had originally been Presbyterian became Congregational in the late eighteenth and nineteenth centuries, Surman also included English Presbyterian and Unitarian ministers, at least before about 1800; these Presbyterians were English not Scottish. It does not include General Baptists (Old or New Connexion), Particular Baptists, Scottish Presbyterians, or ministers of the Presbyterian Church of England (founded by Scottish Presbyterians in the nineteenth century), or Methodists, except incidentally, and in those cases largely because they had been or became Congregational ministers or served Congregational churches. Since modern religious dissent was a consequence of the ejection of about two thousand ministers and teachers from the established church between 1660 and 1662, most of the first generation of nonconformist ministers had served in the Church of England. There are later examples of dissenting ministers who conformed and of a smaller number who left the Church for dissent. These changes can be identified through the Surman Index and the Clergy of the Church of England Database at the clergy database. An index of obituaries in Unitarian periodicals can be found at unitarian obituaries.
Because the original purpose of the index was to create a directory of Congregational ministers, Surman was not much interested in family details – parents, siblings, spouses, or children, unless they too were Congregational ministers. Although he attempted to include the dates of births and deaths where known, he made no serious effort to obtain such details from registers or other sources. There are some laymen included in the database, either because they were educated at a dissenting academy or because they subsequently followed a lay career.