The deployment of decision support aids, electronic referral tools or other novel processes to improve diagnostic or therapeutic performance may also disrupt the flow of the consultation in general practice. Therefore ‘innovations’ or interventions that may result in changes to the structure of the consultation need to be tested in controlled conditions if they are not to harm patient care in practice. We describe a method for conducting ‘Phase 1’ studies of such interventions illustrated by a consultation from one of four studies using actor-patient consultations. The recording of actor-patient consultations is technically challenging. There are some limitations in using volunteers whose skills may be unknown. However, the method allows lay and professional observation about the performance of doctors using new tools which may help to refine the innovations or offer insights into how and why some clinical scenarios impact on the doctor-patient consultation. This method is not a substitute for adequately powered clinical trials; however, it offers a practical approach to developing a complex intervention for subsequent formal evaluation.