You will often come across situations - particularly before 1837 - where the surviving records are inadequate - with missing births/baptisms, burials with no information about the age of the deceased, etc.

An approach which can help in these circumstances is family reconstruction - where all the information for a given surname in the areas, from as many different sources as possible, are collated to see if it is possible to assign everyone into a small number of families.

A simple example is demonstrated in IZARD, Hunsden, mid-18th century, where information from baptism, marriage and burial indexes (ideally this would be extended to include the individual registers) appear to account for all but one member of the family - who may have moved away from the village.