Many scholars have claimed that social work practice relies on tacit knowledge. However, tacit knowledge or "practice wisdom" cannot be critically examined in and of itself. In this article, we hope to make explicit the interventions and outcomes resulting from social workers' tacit knowledge. We used a combination of qualitative and quantitative methods to map interventions in relation to outcomes. Data for the study were derived from a sample of 69 social workers in six family agencies who treated 141 clients within the framework of Systematic Planned Practice. The results demonstrate the viability of practice wisdom for generating testable interventive hypotheses and the usefulness of combining methodologies in practice research.