Mr. Cormac Halpin:

The starting point for the field operation is that we overlay a map of the country with all of the residential address points taken from the geo-directory, which is recognised as the most comprehensive database of addresses in Ireland. We cut the address points up into manageable work areas of approximately 450 dwellings, which we call "numeration areas". These are, in essence, the work units for every enumerator we employ. We create enumerator record books which contain a list of each of those 450 dwellings and an accompanying map which goes with the enumerator record book. The essential job of the enumerators is to account for every one of those dwellings in their areas. As such, they are required to visit each. We employ approximately 4,500 enumerators who are each assigned a work area. Enumerators receive a standard training which is provided by both the CSO and their area managers.

Part of that training required enumerators to learn the different definitions we apply to the dwellings in their areas.

For a particular dwelling to be deemed to be vacant, it must be habitable. That means it must have a door, a roof, walls and windows. I accept that this might not be a particularly nuanced definition in some senses. This is a ten-week operation. The enumerators are not quantity surveyors. We have to be quite blunt in how we define what is a vacant dwelling. That is consistent across the country. Enumerators are not left to their own devices. They are managed quite closely by their area supervisors and are subject to stringent quality control. Area managers visit a sample of the dwellings that each enumerator has declared to be vacant to ensure they are in fact vacant. An enumerator will call to a dwelling at least three times before declaring it to be vacant. I am glad Senator Boyhan said his enumerator called six times. Our experience is that enumerators call many more than three times, partly because they are incentivised to find people in dwellings. They are paid more to collect census forms than to declare dwellings to be vacant. They visit dwellings suspected of being vacant at least three times. They have the capacity to drop in census forms if they believe dwellings may be vacant. They look out for signs that dwellings might be vacant. For example, post might be building up in the letterbox, there might be no cars in the driveway or windows might not be open. They are also required to visit dwellings after census night to ultimately confirm that the dwelling is vacant. It is not a flippant decision. Quite a lot of rigour goes in before a dwelling is declared to be vacant.

Senator Boyhan asked about the reasons dwellings are vacant. We decided to collate this information almost on the hoof during the processing of the census data. We were mindful of the demand for information. We looked at the notes sections of the enumerator reference books, which I mentioned earlier, to see why dwellings were vacant in 60,000 cases. We coded that information as we do with other information across the census and we produced information on that basis. We labelled it quite clearly in our publication that it was experimental data. This is not something we have done previously. We produced this information because we thought it would meet public demand. We think it is a useful contribution to the public debate on this issue. It is certainly something we will seek to formalise to a greater extent in future censuses. I mentioned earlier that we give enumerators quite clear instructions on how to declare a dwelling to be vacant. Determinations in respect of holiday homes are usually made on foot of local consultation. An enumerator will knock on neighbours' doors to make an inquiry about a dwelling that is vacant. He or she might be told by a neighbour that a dwelling is occupied by the owner for certain parts of the year. It is only on the basis of such information that an enumerator will declare a dwelling to be a holiday home. Mr. Dalton mentioned several other dwelling statuses. In all such cases, enumerators are given very clear, simple and straightforward instructions to follow before declaring dwellings to fall into one of those categories.