Introduction

The advances in scientific medicine over the past 50 years have tended to overshadow the importance of applied clinical research, particularly research in primary care. Research into prevention is a good starting point for primary care researchers wanting to reduce the burden of disease, because activities such as vaccination and supporting smoking cessation are among the most effective interventions people can make in primary care. Most burdensome diseases are treated more effectively if they are diagnosed at an early stage. The most important determinant of the outcome of cancer is the stage at which it is diagnosed and hence the point at which treatment is started. Although research on treating acute illness in primary care is essential, this does not imply that it is essential that the effectiveness of every medicine needs to be trialled in primary care. The quality of primary care can often be constrained by lack of evidence about what should be done.