normative need is that which the expert or professional, administrator or social scientist defines as need in any given situation. a desirable standard is laid down and is compared with the standard that actually exists if an individual or group falls short of the desirable standard then they are identified as being in need. thus the BMA nutritional standard is usedas a normative measure of the adequacy of a diet. the incapacity scale developed by townsend and the measure of social isolation used by tunstall are also examples of normative standards used as a basis of need. a normative definition of need is in no sense absolute. it may not correspond with need established by other definition. a further difficulty with the normative definition of need is that there may well be different and possible conflicting standard laid down by difficulty expert . so the normative definition of need may be different according to the value orientation of the expert on his judgements about the amount of resources the should be devoted to meeting the need or whether or not the available skills can solve the problem. normative standards change in time both as a result of developments in knowlege and the changing values of society.