Agencies may provide assistance to individual persons, groups of persons (e.g. support groups) or to other organisations. All of these may be considered clients of an agency. Specific data collections may circumscribe the Type of clients that are included in the collection. For example, at the current stage of development of the Home and Community Care (HACC) Minimum Data Set (MDS), HACC funded agencies are only required to report on clients who are individual persons. Future developments may extend the coverage of the HACC MDS collection to include organisational or group clients.

The definition of a 'client' may also be circumscribed by the definition of 'assistance'. What is included as 'assistance' may depend on what activities are considered significant enough to warrant separate recording and reporting of the nature and/or amount of the assistance provided to a person. For example, an agency worker answering a telephone call from an anonymous member of the public seeking some basic information (e.g. a phone number for someone) would not usually consider that this interaction constituted assistance of sufficient significance to warrant recording that person as a 'client'.

Furthermore, what constitutes 'assistance' may be influenced by the type of assistance the agency was established to provide. In the above example, the agency in question was funded specifically to provide telephone advice, and referral information, to members of the public or specific sub-groups of the public. The agency may have a policy that all persons telephoning the agency for information are classified as clients, albeit anonymous clients.

The level of support or the amount of support given to a person by an agency can also be used to define them as a client or not. For example in the Supported Accommodation Assistance Program (SAAP) National data collection, clients are defined by either taking up an amount of time of an agency; being accommodated by an agency; or by entering an ongoing support relationship with an agency.