Background 1 2 3 5 6 7 urgent  urgent  8 next available routine appointment  9 Recognising the complex nature of this issue, we set out to review the literature. Our main aim was to search the international primary care literature for methods that had been, or were being developed to measure access to GP appointments, focusing on measures using appointment system data. Once identified, existing methods (tools, scales or other instruments) would be compared, with specific attention given to the type and levels of access they aimed to assess. Method family practice health service accessibility  appointments and schedules  research design, health service needs and demand, weights and measures, quality of healthcare, management audit, patient satisfaction, health service needs and demand general practice, access, appointments (same day, urgent, routine) appointment systems, measurement, measures, tools, scales, demand, availability, audit and waiting times 1 12 16 18 21 25 27 21  health service delivery, access to primary care and general practice 6 1 10 11 Studies or articles were included in the review if they described tools, scales, questionnaires or other methods of measuring actual patient access to appointments. We also included descriptions of methods that were currently being developed in this field, provided they had undertaken pilot studies and had completed one data collection exercise. Articles were excluded if they were purely editorial. Results A total of 1763 citations were initially identified and 38 articles retrieved for detailed assessment from the Pubmed and the Medline searches. Clin Psych and ASSIA searches provided some overlap but no new relevant material. The most helpful pointers to relevant publications were obtained from the website searches and personal communications rather than the traditional search engines. Two broad approaches to the measurement of patient access were identified. Firstly, appointment systems in organisations were analysed in differing ways to provide numerical data and, secondly, patient perceptions (reports) of access were evaluated using survey techniques. Methods using appointment system data 1 Table 1 Comparison of methods based on appointments systems to measure access to primary care  Third appointment  21 NEMAS  15 Ledlow  14 Access Response Index AROS  22 Campbell  12 Kendrick  13 Measurement rd  Date of patient call and appointment provided. GP requested and GP allocated. Appointments demanded but not available in US style primary care clinics compared to community clinics. Demand versus availability gap coded into 4 categories. Number of days until next available routine appointment (with any clinician) at 4 pm, every working day Number of appointments provided at the beginning of the day and the number still available. Total number of patients seen during the day, noting the number of 'extras' Number of appointments available at the start of the day and the number of patients seen as 'extras' at the end of the day Frequency of data collection Once a week Continuous Daily Once a day Twice a day Twice a day Weighted for part time staff Yes No No No No No Named clinician access measured Yes Yes No No No No Data analysis Weekly median score and monthly average Computerised Demand versus availability gap Computer to work out 5 day moving average Data related to practice list size, with rates given per 1000 patients Daily tally Results Weekly snapshot of patient access profile Complete computerised analysis of practice appointment system Feedback reports generated to clinic staff Trends across weekly schedules. Bar charts represent number of appointments offered versus number of patients seen. Start of day appointment availability categorised as low, medium and high Graphical display of extras versus number of free appointments during the day Extent of and reason for use Primary Care Collaborative in England. To inform implementation of advanced access 145 teaching practices Audit US Military Clinic Study 10 practices To inform improvement 19 practices Research Study 1 practice Research Study Co-ordination National Primary Care Development Team Department of General Practice, University of Glasgow. Healthcare Programs Central Michigan University. University department of General Practice University Department of General Practice, Edinburgh. Department of Primary Health Care, University of Southampton. 12 13 14 15 16 17 18 19 20 access  21 22 same day  1 Figure 1 AROS scores for routine appointment availability (data from 11 practices)  Methods using patient questionnaires access  2 23 24 25 26 27 28 29 Table 2 Patient survey instruments: items used to determine access perceptions  Survey items Response ratings 23 6. Thinking of times when you want to see a particular doctor: a) 5 point scale, 1 = same day, 5 = more than 5 days   a) How quickly do you get an appointment?    b) How do you rate this? b) Range from 1 = very poor, 6 = excellent  7. Thinking of times when you are willing to see any doctor:    a) How quickly do you get an appointment? 8. Yes / No / Not applicable / Don't know   b). How do you rate this?   8. If you need an urgent appointment to see your GP can you normally get one on the same day?  25 26 What is your opinion of the general practitioner and/or the practice over the past 12 months with respect to: 5 point scale (poor to excellent)  19) Getting an appointment to suit you?   23) Providing quick services for urgent health problems?  28 10) It can sometimes be difficult to get an appointment with my doctor at this surgery. 5 point agreement scale  14) It can be hard to get an appointment for medical care right away.  29 33) Getting an appointment at a convenient time is easy. 5 point agreement scale  34) Appointments are easy to make whenever I need them.   35) It is often difficult to get an appointment with a doctor.   36) It is easy to see a doctor of my choice.  Discussion Principal findings This review of access measurement reveals the heterogeneous nature of the methods and the lack of any widely accepted conceptualisation of patient access. Identified measures are either practice centred using appointment data or patient orientated via surgery satisfaction questionnaires. It is clear that these two methods represent entirely different aims. It is not possible for episodic patient surveys to provide data that has enough currency or accuracy to inform organisational responses to patient demand. emergencies  urgent soon elective Urgent  soon  routine or elective  held  Strengths and weaknesses of the study Multiple search methods were used to ensure that the breadth of literature and online resources were examined as systematically as possible. The searches proved difficult and reflect the emergent status and the diversity of terms used in this area. We may have overlooked methods developed in other healthcare systems. Implications of the findings to healthcare services and research The lack of a widely agreed measurement method to represent patient access to primary care services will make it impossible for practices to compare their response to patient demand with any degree of certainty. The 'third appointment' system is the most widely used method and is currently supported by the National Primary Care Development Team in England (but has no equivalent support in Scotland, Wales or Northern Ireland). It is however a relatively complex manipulation of appointment system data, and incorporates individual clinician availability. It seems from first principles that the important requirements of a tool designed to measure a dynamic concept such as patient access is simplicity and ease of regular data collection, so that longitudinal data patterns capable of indicating trends in organisations can be generated rather than data on individual clinician availability. 30 31 32 33 34 35 Conclusion The two approaches of either using patient questionnaires or appointment system data to measure access are methods that represent entirely different aims. The latter method when used to represent patient waiting times for 'routine' elective appointments seems to hold promise as a useful tool and this avoids the definitional problems that surround 'urgent' appointments. The purpose for which the data is being collected needs to be borne in mind and will determine the chosen methods of data retrieval and representation Competing Interests The authors of this article have piloted the AROS Index. Authors' Contributions Peter Edwards, Melody Emmerson and Glyn Elwyn were involved in the development of the Aros index. Wendy Jones and Glyn Elwyn conducted the Aros pilot study and the literature review with contributions from Adrian Edwards and Richard Hibbs. Pre-publication history The pre-publication history for this paper can be accessed here: