There are also features of judicial activity which affect the impact that judges’ decisions can expect to have. So far as judicial review seeks to influence administrative activity, it can be seen as performing three different functions: directing, limiting and structuring decision making. A court may hold that a body has a duty to act in a particular way on the facts of the case, and direct it to comply. Directing decision making in this way usually gives effect to legislative provisions. it may achieve a high public profile and have significant resource implications, especially where the case is one of a number of similar ones and the duty will be costly to fulfil, and to that extent it may affect a wide range of functions which the authority exercises by forcing it to re-examine its priorities.” (The sane happens in decisions about tort liability of public authorities.) However, this is unlikely to affect day-to-day administrative practices very much. Limiting a public authority to keep it within the range of activities, powers or purposes allocated to it by statute can have a greater effect on day-to-day administration, and may make it more difficult to achieve its goals, but can be justified by the principle of legality. Structuring decision making goes further, and has the greatest potential for affecting administrative practices. It provides principles to guide decision-making by providing for fair procedures, and reasoned and reasonable decisions. It is here that judicial review intrudes most closely into the field of good administration, for good or ill?“ This is why it is not surprising that studies of the effect of judicial review on prison administration have concluded that the effect has been greatest where decisions relate to procedural matters, such as disciplinary procedures and the right to make representations in respect of parole decisions, and far less extensive in relation to the conditions of imprisonment and regimes of prison governance.” However, even in relation to ‘structuring’ decisions, the tendency of judicial review to focus on the facts of a particular case, rather than to examine the matrix of decisions and procedures from which it emerges, may distort judicial appreciation of the context and so limit the usefulness of the case in shaping future decision making practices.