Sackett et al (1997:22) argue that almost every time a medical practitioner encounters a patient they will require new information about some aspect of their diagnosis, prognosis or management. This is no less true for other health professionals. They note that there will be times when the question will be self-evident or the information will be readily accessible. This is increasingly the case as sophisticated information technology gets nearer and nearer to the bedside. Even so, there will be many occasions when neither condition prevails and there will be a need to ask an answerable question and to locate the best available external evidence. This requires considerably more time and effort than most health professionals have at their disposal and the result is that most of our information needs go unmet.

The first step is to have a question that is answerable. Asking answerable questions is not as easy as it sounds, but it is a skill that can be learned. Sackett et al (1997:30) offer some useful advice in the context of evidence-based medicine and the effectiveness of interventions. These sources can be extended beyond questions of effectiveness, to consider the appropriateness and feasibility of practices. The source of a clinical question (adapted from Sackett et al 1997) includes:

• Assessment: how to properly gather and interpret findings from the history and physical examination and care

• Aetiology: how to identify causes for problems

• Differential diagnosis: when considering the possible causes of a patient’s clinical problems, how to rank them by likelihood, seriousness and treatability

• Diagnostic tests: how to select and interpret diagnostic tests to confirm or exclude a diagnosis, based on considering, for example, their precision, accuracy, acceptability, expense and safety

• Prognosis: how to gauge the patient’s likely clinical course and anticipate likely problems associated with the particular disease and social context of the person

• Therapy: how to select therapies to offer patients that do more good than harm and that are worth the efforts and cost of using them

• Prevention: how to reduce the chance of ill health by identifying and modifying risk factors, and how to detect early problems by screening and patient education

• Meaningfulness: how to understand the experience of patients and the social context within which practice takes place

• Feasibility: how practical it is to implement a practice within a given clinical setting, culture or country, and

• Self-improvement: how to keep up to date, improve your clinical skills and run a better, more efficient clinical service.

Drawing on this, a clear, well-formulated question is developed to give focus to the systematic review. A clearly defined question should include specific details on:

• Participants: Participants should be defined clearly and this should include their condition (e.g. people with a confirmed diagnosis of emphysema), the population characteristics (e.g. females aged 15–20 years), and the setting (e.g. in hospital medical wards).