Index-Based Inequality in Quality of Care: An Empirical Comparison of Apples and Pears

Figures & data

Figure 1 Graphical illustration of the income-related inequality in quality of care using absolute concentration index (2004–14).

Figure 2 Graphical illustration of the income-related inequality in quality of care using slope index of inequality (2004–14).

Table 1 Study Population

		N	Mean	Range
				25%	50%	75%
Quality of care		110,848	70.40	57.14	75.00	90.00
	2004–2008	52,767	66.24	50.00	71.43	85.71
	2009–2014	58,081	74.18	66.67	76.92	90.00
Family income (in thousands)		100,722	270.91	156.25	212.34	319.02
	2004–2008	47,762	257.42	150.16	202.67	302.15
	2009–2014	52,960	283.08	162.00	222.86	334.91
			n (%)
		N	Primary	Lower Secondary	Upper Secondary	Short Tertiary	Bachelor or Equivalent	Master or Equivalent	Doctorial or Equivalent
Educational level		97,512	149 (0.15)	47,102 (48.30)	35,716 (36.63)	2141 (2.20)	8966 (9.19)	3353 (3.44)	85 (0.09)
	2004–2008	43,841	66 (0.15)	22,314 (50.90)	15,556 (35.48)	887 (2.02)	3642 (8.31)	1353 (3.09)	23(0.05)
	2009–2014	53,671	83 (0.15)	24,788 (46.19)	20,160 (37.56)	1254 (2.34)	5324 (9.92)	2000 (3.73)	62 (0.12)

Table 2 Univariate Indices of Inequality in Quality of Care

	2004–08	2009–14	Absolute Difference	95% CI	Relative Difference
N	52,767	58,081
ACII	0.648	0.462	−0.187	(−0.188; −0.185)	−29%
ARCII	0.245	0.156	−0.089	(−0.090; −0.088)	−36%
SRCII*	0.480	0.447	−0.033	(−0.035; −0.031)	−7%

Note: *Negative operational signs are ignored.

Abbreviations: CI, confidence interval; ACII, absolute concentration index; ARCII, attainment relative concentration index; SRCII, shortfall relative concentration index.

Table 3 Bivariate Indices of Inequality in Quality of Care

		2004–08	2009–14	Absolute Difference	95% CI	Relative Difference
Income related
	N	47,762	52,960
	ACII	0.068	0.043	−0.025	(−0.032; −0.017)	−36%
	ARCII	0.025	0.015	−0.011	(−0.014; −0.008)	−43%
	SRCII*	0.050	0.042	−0.009	(−0.014; −0.003)	−17%
	SII	8.279	5.214	−3.065	(−4.650; −1.479)	−37%
	ARII	1.165	1.091	−0.074		−6%
	SRII*	0.740	0.779	0.039		5%
Education related
	N	43,841	53,671
	ACII	0.024	0.022	−0.001	(−0.008; 0.006)	−5%
	ARCII	0.009	0.008	−0.001	(−0.037; 0.001)	−14%
	SRCII*	0.018	0.022	0.004	(−0.009; 0.002)	21%
	SII	1.334	4.803	3.469	(−1.701; 8.639)	260%
	ARII	1.066	1.055	−0.011		−1%
	SRII*	0.876	0.856	−0.020		−2%

Note: *Negative operational signs are ignored.

Abbreviations: CI, confidence interval; ACII, absolute concentration index; ARCII, attainment relative concentration index; SRCII, shortfall relative concentration index; SII, slope index of inequality (rank income/100); ARII, attainment relative index of inequality; SRII, shortfall relative index of inequality.

Table 4 SII Under Different Definitions of Income

	Observations in Model (n)	2004–08	2009–14	Absolute Difference	95% CI	Relative Difference
Raw income	99,662	10.087	6.539	−3.548	(−4.620; −2.477)	−35%
Log(income)	98,263	10.157	6.528	−3.629	(−4.702; −2.555)	−36%
Income/100	14,165	8.279	5.214	−3.065	(−4.650; −1.479)	−37%
Income/1000	2696	5.260	4.822	−0.438	(−3.441; 2.566)	−8%

Figure 3 Slope inequality indices over time.