Table 1: Measures of Continuity of Care.

Name of Index	Description	Score Range	Index Measures				Strengths	Weaknesses
			Durationa	Densityb	Dispersionc	Sequenced
Usual Provider of Continuity (UPC) index	The number of visits to a usual provider in a given period over the total number of visits to similar providers	0 to 1	Yes	Yes	No	No	Since a ‘usual provider’ is defined, it may be useful in analyzing the role of other health providers in addition to physicians	Only assesses visits with usual provider, other providers not included in the index Not independent of utilization levels Measure decreases as number of visits increases
Continuity of Care (COC) index	Measures both the dispersion and concentration of care among all providers seen	0 to 1	Yes	Yes	Yes	No	Sensitive to shifts in the distribution of visits among providers Good mathematical performance; tends to have a mean of 0.5 and a large coefficient of variation	May mask important differences in sequencing of care Mot independent of utilization levels Measure decreases as number of visits increases Measure falls rapidly with increasing number of providers seen
Modified Continuity Index (MCI)	Measure of concentration of care in population of patients calculated by dividing the average number of visits by a group by the average number of providers in the a population	0 to 1	Yes	Yes	Yes	No	Requires summary utilization measures only (compared with COC which requires more utilization data)	Extremes of continuity not reflected in measure (i.e., 2 visits to same provider yields an intermediate result rather than perfect continuity)
Modified Modified Continuity Index (MMCI)	Measure of concentration of care with providers at the individual patient level Developed to account for problems of COC and MCI indices	0 to 1	Yes	Yes	Yes	No	Requires summary utilization measures only (compared with COC which requires more utilization data) Not overly sensitive to large number of providers	No sequential data captured
Sequential Continuity (SECON) index	Fraction of sequential visit pairs where the same provider is seen	0 to 1	Yes	Yes	No	Yes	Sensitive to shifts in sequence of visits Potentially useful as measure of amount of inter-provider communication necessary because of transfers of care	Insensitive to the distribution of visits among providers if sequencing remains constant

^aDuration refers to the length of time with a particular provider.

^bDensity refers to the number of visits with the same provider over a defined time period.

^cDispersion refers to the number of visits with distinct providers.

^dSequence refers to the order in which different providers are seen.

Source: Reid et al, 2002. (3)