Attribution takes account of the fact that outcomes will also be influenced by other organisations and factors, especially where the stakeholders’ objectives can only be achieved through the combined efforts of more than one organisation. For example, while MillRace IT trains people recovering from mental ill health, InterAct works with the participants before they enter the training programme, and in some cases, family members at home support the participants throughout the training period. Therefore, when a participant moves on to employment, MillRace IT cannot take all of the credit for the outcome. When we calculate the SROI, we address the extent to which an organisation can take credit for the outcome produced.
Source: Measuring value: a guide to social return on investment http://www.sroi-uk.org/component/option,com_docman/task,cat_view/gid,25/Itemid,38/