Today, about half the group worked at the Valuation Office with the assistance of Helen Kelly. After Griffith's Valuation was completed, updated valuations were done on regular intervals noting any changes that had taken place since the previous valuation. It's important to remember that although we sometimes refer to Griffith's as a "census substitute," it is really a tax list. As such, the records had to be kept up to date so the proper taxes would be paid.
Once you have found your family in Griffith's you are ready to visit the Valuation Office to research in the Revision or Cancelled Books. Although some of these books are available at the Family History Library on microfilm, working with the originals in the Valuation Office provides the visual cue of different color ink to track when changes were made. The Valuation Office holds the original books for the Republic of Ireland; PRONI holds the books for the Northern counties.
To begin, you take your page from Griffiths and note the County, Barony, Townland and DED (District Electoral Division). When you arrive at the Valuation Office one of the staff will input the information and bring you a set of books that contain the records.
Every few years, after numerous changes had been made, the most recent information was copied into a new book and the old book was Cancelled. The individual books have been bound together and depending on the number of town lands, they may contain from two to six or seven cancelled books. You begin by going to the oldest book and starting at the back (they're bound in reverse order) look for your townland in the index of the last book. Go the the first page of the townland as listed in the index, then find the property number as shown on Griffith's and note any changes. When the name of the occupier is crossed out and another name written in, some type of life event has happened. If the surname of the replacement name is the same, it would usually indicate a death or emigration. Based on the date you might want to check the civil registration index (after 1864) to see if there was a death. Some of these books now go up into the 1990s.
The Valuation Office also has copies of the Ordnance Survey maps with the corresponding numbers to the left column of Griffith's.