The IQCODE takes 10–25 min to complete depending on the form chosen (long/short) and whether it is administered in pen and paper form or electronically. It is generally perceived as easy to answer and can be mailed to informants or administered by telephone or by computer (although we are not aware of any validation data with non-pen-and-paper administration media).

Scoring the IQCODE requires adding up all ratings and dividing by the number of items, thus yielding a measure ranging from 1 to 5. An alternative scoring strategy used by some investigators involves using the sum of all responses as a summary measure. Norms have been developed by Jorm and Jacomb for 5-year age groups from 70 to 85+ years [11]. However, the use of an absolute cut-off, ranging from 3.3 to 3.6 in community samples to 3.4–4.0 in patient samples, is typically preferred and easier to communicate. A practical way of selecting a valid and effective cut-off is to identify studies (see Table 13.2) with characteristics most similar to the target population in the planned study and apply their cut-offs. Alternatively a weighted average computed from Table 13.2, of 3.3 for community samples and of 3.5 in patient samples, is also defensible (also note below, see Sect. 13.6, findings from systematic reviews which are consistent with the approach suggested above).