This survey became known as "Griffiths Valuation" after Richard Griffith who was the director of the office at that time. The survey was used to determine the amount of tax each person should pay towards the support of the poor within their poor law union. This involved determining the value of  all privately held lands and buildings in rural as well as urban areas to figure the rate at which each unit of property could be rented year after year. The resulting survey was arranged by barony and civil parish with an index to the townlands appearing in each volume. Griffith's Valuation can be used as an excellent census substitute for the years after the Great Famine as censuses prior to 1901 were destroyed.