Practitioner research should be sufficiently trustworthy "and" useful. We argue, however, that although criteria of trustworthiness are rather well developed, criteria of usefulness are not. As a result, the long-term impact of practitioner research is rather disappointing because, we contend, it tends to lack practicality. We used theories of classroom ecology, goal systems and how people make decisions in complex situations, to conceptualise practicality from a teacher's perspective. By applying our theoretical framework to the case of Jane we provide insight into how and why trustworthiness and usefulness can be met while practicality is typically undermined. Jane conducted an excellent practitioner research project in the context of her teacher training under what would be considered 'ideal' conditions, but the long-term impact on her teaching practice was low. We conclude with suggestions for making practitioner research more attuned to practicality, i.e. the nature of practice and practical decision making.