Table 1.

Average (SD) Case Mix Index Over Time

Variable	N	1996	2009	%Change	P value
All Hospitals	364	1.04	1.18	13%	<0.0001
Hospital ownership
Public	69	0.99 (0.21)	1.05 (0.22)	6%	<0.0001
Private for-profit	73	1.02 (0.25)	1.25 (0.40)	22%	<0.0001
Private nonprofit	219	1.07 (0.21)	1.20 (0.23)	13%	<0.0001
Teaching affiliation
Nonteaching	280	1.01 (0.19)	1.15 (0.27)	14%	<0.0001
Public Teaching	23	1.12 (0.24)	1.21 (0.26)	8%	<0.0001
Private Teaching	59	1.15 (0.28)	1.34 (0.29)	17%	<0.0001
Trauma levels
0	303	1.03 (0.21)	1.17 (0.29)	14%	<0.0001
4	7	0.90 (0.11)	0.92 (0.11)	2%	0.646
3	8	1.20 (0.27)	1.25 (0.18)	4%	0.182
2	31	1.08 (0.14)	1.21 (0.19)	13%	<0.0001
1	13	1.25 (0.23)	1.45 (0.29)	16%	0.0007
1-public	8	1.27 (0.28)	1.42 (0.30)	13%	0.0018
1-private (nonprofit)	5	1.22 (0.15)	1.50 (0.29)	23%	0.030
Hospital bed number
1–49	51	0.95 (0.21)	1.10 (0.44)	16%	0.161
Public	18	0.90 (0.14)	0.92 (0.14)	2%	0.406
Private	33	0.99 (0.23)	1.15 (0.54)	16%	0.1862
50–99	42	0.96 (0.15)	1.11 (0.22)	16%	<0.0001
Public	7	0.93 (0.14)	0.96 (0.14)	3%	0.664
Private	35	0.97 (0.15)	1.12 (0.15)	15%	<0.0001
100–249	155	1.02 (0.23)	1.17 (0.26)	15%	<0.0001
Public	22	0.94 (0.16)	1.02 (0.16)	9%	0.002
Private	133	1.04 (0.24)	1.20 (0.26)	15%	<0.0001
250–350	54	1.11 (0.18)	1.26 (0.19)	14%	<0.0001
Public	7	1.08 (0.12)	1.24 (0.16)	15%	0.003
Private	47	1.13 (0.18)	1.26 (0.20)	12%	<0.0001
>350	60	1.16 (0.20)	1.28 (0.25)	10%	<0.0001
Public	15	1.16 (0.26)	1.26 (0.30)	8%	0.005
Private	45	1.15 (0.18)	1.31 (0.24)	14%	<0.0001