Physiology and social conventions may both set limits to the range of demographic phenomena, and therefore permit tests to be made on FRFs after their input into a machine-readable form. The tests are made in order to detect errors that may have been made either in the original process of reconstitution or subsequently, in the course of data input. As a result the quality and consistency of the data used in demographic tabulations is enhanced. The following tests were carried out on all the FRFs from the 26 parishes that form the empirical basis of this book.

On all individuals

1. 1 That the date of birth was less than or equal to the date of baptism. Note that if the date of birth was not known directly from the register it was set equal to the date of baptism but given a weight, so that knowledge of the provenance of the information could be used as appropriate in subsequent tabulations.

2. 2 That, similarly, the date of death was less than or equal to the date of burial. Here, too, if the date of death was not recorded in the register, it was set equal to the date of burial with the addition of a weight.

3. 3 That the date of birth was less than or equal to the date of death.

4. 4 That the date of death was less than the date of birth plus 105 years.