The American psychologist Maslow established a seminal hierarchy of need when attempting to formulate a theory of human motivation (Maslow, 1954). In Maslow's model, fundamental physiological needs (such as the need for food) underpin the higher needs of safety, love, self-esteem and self-actualisation. He proposed that people are motivated by the requirement to meet these needs, and that higher needs could be met only once the lower and more fundamental needs were met. This approach can be illustrated by the example of a homeless man, who is not concerned about his lack of friends while he is cold and hungry. However, once these physiological needs have been met he may express more interest in having the company of other people (Slade & McCrone, 2001).
Since the work of Maslow, several approaches have been developed for defining need with respect to healthcare. The sociologist Bradshaw (1972) proposed a ‘needs taxonomy’ with three types of need: (1) felt or expressed need that is mentioned by the user; (2) normative need which is assessed by the expert; and (3) comparative need, which arises from comparison with other groups or individuals. Such an approach helps to emphasise that need is a subjective concept, and that the judgement of whether a need is present or not will, in part, depend on whose viewpoint is taken. Other, somewhat more philosophical approaches to needs have also been proposed (e.g. Mallman & Marcus, 1980; Liss, 1990).
In the Medical Research Council (MRC) Needs for Care Assessment (NCA), a need is defined as being present when a person's functioning falls below, or threatens to fall below, some specified level, and when there is some remediable, or potentially remediable, cause (Brewin et al, 1987). Slade (1994) discussed the issue with respect to differences in perception between the users of mental health services and the involved professionals, and he argued that once differences are identified, then negotiation between staff and user can take place to agree a care plan.
Despite the common view that services should be based upon assessed needs, there is no consensus on how needs should be defined (Holloway, 1994) or on who should define them (Slade, 1994).