While the key informant method may identify some people with disabilities, particularly those with more obvious types of impairment, assessing functioning of individuals through observation or assumed knowledge of individuals is subjective and can be very inaccurate.
This method might be appropriate in some situations if programs are interested in getting a preliminary count of the number of persons with functional limitations in area of interest. It must be understood that the estimates will likely be an underestimate but it will be difficult to determine the magnitude of the underestimate. This method also doesn’t allow for disaggregation of by disability and other characteristics (i.e. age, gender). This approach could be seen as a first step to be followed up by a broader data collection at the individual level such as using the WG Short Set on a representative sample of the community (e.g. one in ten households, or one in five people at a community event).
In some data collection efforts, key informants used tend to come from the membership of Disabled People Organizations because they are easy to locate. It should be kept in mind that this is not a representative group. They tend to be more knowledgeable and have greater access to services.
Using the key informant method to identify people with disabilities for services will likely miss many persons with disabilities who could be program participants.