Nature and quality of the information in the enumerators' books The original householders' schedules used in these censuses (stage 1) have been destroyed and there survive only the enumerators' books and the printed abstracts (i.e. Stages 2 and 3 in the census process). Errors in census material can be
identified only in the two surviving sources, though many such errors would originate at Stage 1. 16 Broadly speaking, errors in census data may be classified under two headings:
ERRORS OF COVERAGE
1871 1861 1851
ERRORS OF CONTENT
It would not be unreasonable to suspect the censuses of the mid-nineteenth century of containing errors at least as large. Krause has inferred omission in the child age groups by comparing the sex ratios for 1841 with those implied by the English Life Table No.3. Males per 1,000 females in age groups 0-4 and 5-9 in the census were 991 and 1001 respectively, while the corresponding ratios from the life table were 1014 and 1010. This suggests omission, but it must be remembered that the method depends upon the accuracy of the data on mortality from which the life table was drawn up.