Chronic Poverty Research Centre

Impact assessment is a broad field. The impact of the full range of development interventions (projects, programmes, sector wide support and donor country strategies and macro economic growth and programme aid support) can be assessed using qualitative or quantitative approaches or a mix. The objectives of the impact assessment exercise may differ, as may the intended end user of the information. This summary provides a simple overview of key issues and approaches.

Defining Impact

Forms of impact assessment (IA) vary. IA can focus on whether an intervention has succeeded in terms of its original objectives, or it may be a wider assessment of overall changes caused by an intervention – positive and negative, intended or unintended (Roche, 1999:21).

In order to conduct an effective impact assessment one must first be clear about what one considers to be an impact. Roche defines impact as ‘the systematic analysis of the lasting or significant changes - positive or negative, intended or not – in people’s lives brought about by a give action or series of actions.’ (1999:21). It can be useful to distinguish between the impacts of an intervention and its outcomes. For example outcome or effect of a legal rights project might be increased use of the legal system to claim a right whereas its impact might be the change in an individual’s quality of life (Roche, 1999:22).

Fig. 1: Distinguishing between efficiency, effectiveness, consistency and impact

 Source: Roche, 1999: 23, adapted from Willot, 1985.

Impact assessments might also wish to examine the efficiency, effectiveness, consistency or impact of an intervention (Roche, 1999:22).

Table 1: Efficiency, effectiveness, consistency and impact

Focus of impact assessment	Purpose
Efficiency	Relates inputs to outputs Could the same results have been achieved more cheaply? Would a few more resources achieved much better results?
Effectiveness	To what extent has the intervention achieved its objectives?
Consistency	Were intervention methods/ approaches consistent with the outcomes achieved? E.g. using non-participatory project design and implementation would not be consistent with empowerment objectives
Impact	To what extent has the intervention changed the lives of the intended beneficiaries?