2.6 The first step is to carry out an overview to ensure that two pre-requisites are met: firstly, that there is a clearly identified need; and secondly, that any proposed intervention is likely to be worth the cost. This overview must include an analysis of the negative consequences of intervention, as well as the results of not intervening, both of which must be outweighed to justify action. In many cases, the preliminary step will involve research to set out the scope of the issue to be addressed, and the reasons for intervention.