Title: How Can We Improve Guideline Use? a Conceptual Framework of Implementability

This article represents an important contribution to the field of implementation research and practice. However, the authors make claims about the nature of their review process that are not entirely substantiated. First, the authors suggest that their review is based on a meta-narrative approach. This approach is recommended when 'there is complex evidence.... in a challenging methodological area', particularly where the literature is sought from a number of different disciplinary areas or research traditions. If this was the approach adopted here the authors need to explain the process by which they assimilated and mapped the different strands of research, how the issue of guideline features were differentially characterised by the different professional or disciplinary groups etc. Second, the review is relatively narrow, focusing only on those articles that have 'described guideline features desired by, or influencing the behavior of health professionals'. Moreover, the search terms are also limited, using the term practice guideline, when terms such as procedure, clinical protocol, clinical pathway might also have produced relevant material. There is a large literature, which the authors have contributed to, that examines attitudes to clinical guidelines/protocols. Although participants may not be asked to consider specific features of the guidelines that support compliance in these studies, they do often refer to such features or these might be inferred from what they are saying. For example, in our own work on compliance with clinical protocols (Lawton and Parker, 1999) participants were concerned that evidence goes out of date quite quickly and there is a need to update and revise protocols. The need to include a review date could, therefore, be interpreted as a useful feature of guidelines. Other participants were not clear about exactly how they should use a guideline and whether this differed depending on your role (e.g. was an inexperienced nurse or junior doctor required to adhere strictly to the guideline whilst a more experienced member of staff might deviate). The need for guidance on the level of compliance required for different aspects of a clinical guideline might have been extrapolated from these suggestions.