Measure | Description | Range | Concept * | Formula | Interpretation | Number of papers using this index |
---|---|---|---|---|---|---|
1.Bice & Boxerman index (COCI) | the degree to which patient visits are distributed among different physicians | 0 (all visits to different providers) to 1 (all visits to the same provider) | dispersiona densityb | \(\large \frac{{\sum }_{i=1}^{M}{n}_{i}^{2}-N}{N(N-1)}\) | N-total number of visits, ni number of visits with provider i, M-total number of providers | 35 |
2.Usual Provider of Care (UPC) | the proportion of visits with a usual provider | 0 (no visits to the usual provider) to 1 (all visits to the usual provider) | density | \(\large \frac{{{max}_{i=1,\dots M} n}_{i}}{N}\) | N- total number of visits, ni – number of visits with provider i, M-total number of providers | 14 |
3.Most Frequent Provider Continuity (MFPC) (similar to UPC)** | defines the primary provider as the one seen most frequently | 0 (no visits to the provider) to 1 (all visits to this providermost frequent provider) | density | \(\large \frac{max({n}_{1},{n}_{2}\dots , {n}_{M})}{N}\) | N - total number of visits, ni - number of visits with provider i (i=1,…M), M-total number of providers | 2 |
4.Modified, Modified Continuity Index (MMCI) | the extent to which a patient concentrated her/his visits with the same healthcare provider | 0 (all visits to different providers) to 1 (all visits are to the same provider) | dispersion | \(\large \frac{1-\frac{M}{N+0.1}}{1-\frac{1}{N+0.1}}\) | M -number of different providers and N- total number of visits. | 5 |
5.Sequential Continuity of Care index (SECON) | the proportion of sequential visits that were with the same provider, i.e. same provider being seen at both the previous and current visits | 0 (no sequential visits to the same provider) to 1 (all sequential visits to the same provider) | sequential c | \(\large \frac{{\sum }_{j=1}^{n-1}{\text{c}}_{\text{j}}}{n-1}\) | if the visit j and the subsequent visit (j + 1) are to the same provider then cj = 1, and cj = 0 if otherwise; n-1- sequential pairs of visits | 5 |
6.Herfindahl Index | indicator of provider concentration, physician’s share of a patient’s visits. | 0 (less-dominant providers, not concentrated) to 1 (all visits to the same provider, very concentrated) | concentrationd | \(\large {\sum }_{i=1}^{M}{\left(\frac{{n}_{i}}{N}\right)}^{2}\) | ni - visits for patients to an individual provider i, and N - total number of visits, M-total number of providers | 1 |
7.Care density | reflect how frequently patient’s doctors collaborate/ share patients with one another | 0 (no collaboration/ no shared patients) to ∞ (extreme collaboration/ all patients of all doctors are shared) | density; level of shared patients between providers | \(\large \frac{{\sum }_{i=1}^{m}{\text{w}}_{\text{p,i}}}{{\text{M}}_{\text{p}}({\text{M}}_{\text{p}}-1)/2}\) | Mp - number of distinct doctors that patient p saw, m - total number of possible pairs of doctors, and wp,i - number of shared patients for each pair of doctors. The numerator is the total number of instances of patient sharing over a time period (e.g. a year) among a patient’s doctors. The denominator is the total number of pairs of doctors for that patient. | 3 |
8.Clinician Index | the proportion of visits with primary clinician out of all ambulatory visits | 0 (no visits to the primary clinician) to 1 (all visits to the primary clinician) | density | np/Na1 | np - number of ambulatory visits to a primary clinician and Na1 - number of ambulatory visits in the 1st year | 1 |
9.Site Index | the proportion of visits with primary site out of all visits | 0 (no visits to the primary site) to 1 (all visits to the primary site) | density | np/N1 | np - number of visits to a primary site and N1 - total number of visits in the 1st year | 1 |
Compound Indices | ||||||
10.Integrated Continuity of Care index (ICOC) | ICOC is a linear combination of three indices UPC, COC, SECON via Principal Component Analysis (PCA) | 0 (no visits to the same provider) to 1 (all visits to the same provider) | dispersion; density; sequence | ICOC=(β1 UPC+ β2COC+β3SECON)/ (β1+ β2+ β3) | ß1, ß2, and ß3 is the first principal component Eigenvector of the PCA result, which used the weighted means of the variables for each type of index | 1 |
11.Composite index (COMP) | Composite index, derived by adding the score values of the four commonly used COC indices (COCI, UPC; MMCI, SECON) and dividing by four | 0 (no visits to the same provider) to 1 (all visits to the same provider) | dispersion, density, sequence | (UPC+COCI+MMCI+SECON)/4 | UPC - usual provider of care index, COCI - Bice& Boxerman index, MMCI - Modified modified continuity index, SECON - sequential continuity index | 1 |
12.CI Alpha Index | weighted average of the concentration of providers seen and sequential continuity; KL represents Kullback-Leibler information index showing the degree of concentration relative to no concentration at all | 0 (a different provider is seen for each patient visit, maximum dispersion in both provider concentration and visit sequence) to 1(the same provider is seen at every visit) | concentration and sequence | CIα = αKL* + (1 - α) SECON, α ϵ [0, 1]; \(KL= log M+ {\sum }_{i=1}^{M}\frac{{n}_{i}}{M} \times log \frac{{n}_{i}}{M}\); and \(KL*=\frac{KL}{\mathit{log}M}\) | α is a predetermined weight that is applied to both KL* and SECON; M - total number of providers and ni is number of visits with provider i. | 1 |