Measuring the impact of microfinance programmes on client businesses and proving that changes can be attributed to the intervention are notoriously difficult. In response to this, some argue that client
loyalty is sufficient evidence of client satisfaction and of positive impact, and that further measurement is unnecessary. This article argues against this: impact assessment is necessary not only to demonstrate
to donors that their interventions are having a positive impact, but also to provide information that allows MFIs to improve their services, and thus improve impact. The article describes the move away
from donor-led impact events, towards more practitioner-focused processes, and outlines the experience of individual organizations and international projects, most notably the AIMS project, in developing
impact assessment that is more responsive to practitioner needs. Practitioner-focused impact assessment looks at how impact information can feed into management and product design processes, and provide
frequent and timely information. Many challenges remain, particularly in terms of ensuring a diversity of approaches and applications for IA, and the inclusion of a range of stakeholders in defining what
should be included in the impact assessment process, and in the analysis and use of results. These challenges are the focus of a Ford Foundation sponsored action-research programme, Imp-Act.