Table 1.

A comparison of four of the methods for measuring continuity in general practices

	UPC	Bice–Boxerman	SLICC	OPR
Ease of calculation/understanding	Easy Calculated by dividing a patient’s appointment count with the most-seen GP by each patient’s total appointment count Mean often used as summary statistic for group of patients	More difficult Calculated for each patient using the formula COC = ((SUM(nj2)) − n)/(n(n − 1)) from j = 1 to j = s, where n is the total number of consultations, nj is the number of consultations to GP j and s is the total number of GPs seen by the patient Mean often used as summary statistic for group of patients	Easy Calculated for group of patients (often a GP’s list) by dividing the group’s number of appointments with the named/list-holding GP by the total number of appointments for the group Expressed as a percentage	Easy Calculated for a list-holding GP by dividing appointment count with patients on their own list by the total number of appointments with that GP Expressed as a percentage
Level of measurement	Patient	Patient	Appointments for a group of patients	A single GP’s appointments
Minimum requirements	Two appointments in timeframe	Two appointments in timeframe, three more usual	A pre-specified named GP for each patient	A pre-specified named GP for each patient
Minimum timescale	If the timescale is too short, <1 year, most patients excluded It then becomes a measure of frequent-attender continuity	If the timescale is too short, <1 year, most patients excluded It then becomes a measure of frequent-attender continuity	Can be measured monthly	Can be measured monthly
Strengths	Works for any GP No requirement for named GP Easy to calculate and understand Patient-level measure so allows comparisons between individuals	Takes into account continuity with more than one GP No requirement for named GP Patient-level measure so allows comparisons between individuals	Easy to understand and calculate Can be used in statistical process control charts Good for monthly measurement Includes all appointments and all patients Patient perspective	Easy to understand and calculate Useful for looking at continuity and workload from the GP perspective Can be used in statistical process control charts Good for monthly measurement Includes all appointments and all patients
Limitations	Less useful for short-term measurement Does not take into account team continuity Bias towards frequent attenders if the timescale is too short Upwards skew if patients with only two appointments included Sometimes most-seen provider is a locum or registrar	Less useful for short-term measurement Bias towards frequent attenders if the timescale is too short	Requires a named GP who has seen the patient before or will again. High turnover of patients or GPs may reduce this Requires the ‘usual’ or named GP field to be correct and up-to-date Does not take into account team continuity	Not patients’ perspective A GP could see only their own patients but, if the list size were too high, their patients would not see their own GP very often To be meaningful, practice needs to be using personal lists Does not take into account team continuity
Possible adaptions	Could be adapted so that the ‘usual’ provider is a pre-specified named GP Could be used to identify which GP the patient sees the most when setting up GP lists A cumulative measure of the previous year to date could be used for regular monitoring	A cumulative measure of the previous year-to-date could be used for regular monitoring	Could be adapted to measure the percentage of appointments with both/all the GPs within the micro-team	Could be adapted to measure the percentage of micro-team GP appointments with patients on the lists of both/all the GPs within the micro-team

COC = Continuity of Care. OPR = Own Patient Ratio. SLICC = St Leonard’s Index of Continuity of Care. UPC = Usual Provider of Care.