Table 3 Results of the econometric models
Condition | Year | OLS with logarithm of case volume | OLS with case volume tertiles (reference group: low case volume) | OLS with binary variable whether minimum volume threshold is achieved | Number of | ||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
Medium case volume | High case volume | ||||||||||
Coeff. | S.E. | Coeff. | S.E. | Coeff. | S.E. | Coeff. | S.E. | Hospitals | Patients | ||
Liver | 2005 | −0.0324* | (0.0175) | −0.0118 | (0.0518) | − 0.0513 | (0.0354) | −0.0531 | (0.0588) | 22 | 906 |
2006 | −0.0331 | (0.0267) | −0.0027 | (0.0356) | −0.0441 | (0.0513) | −0.0383 | (0.0448) | 22 | 965 | |
2007 | − 0.0414 | (0.0255) | − 0.0263 | (0.0520) | − 0.0279 | (0.0381) | − 0.1285* | (0.0732) | 22 | 1064 | |
Kidney | 2005 | −0.0026 | (0.0067) | 0.0017 | (0.0057) | −0.0010 | (0.0066) | −0.0035 | (0.0129) | 42 | 2610 |
2006 | 0.0001 | (0.0055) | −0.0043 | (0.0062) | 0.0050 | (0.0059) | −0.0013 | (0.0128) | 42 | 2699 | |
2007 | −0.0102 | (0.0064) | −0.0070 | (0.0074) | −0.0065 | (0.0072) | −0.0539*** | (0.0156) | 42 | 2885 | |
Oesophagus | 2005 | −0.0292*** | (0.0081) | −0.0098 | (0.0166) | −0.0445* | (0.0250) | −0.0476*** | (0.0177) | 428 | 2898 |
2006 | −0.0306*** | (0.0074) | −0.0284* | (0.0166) | −0.0668*** | (0.0203) | −0.0422*** | (0.0157) | 405 | 3107 | |
2007 | −0.0267*** | (0.0075) | −0.0159 | (0.0157) | −0.0262 | (0.0203) | −0.0186 | (0.0147) | 415 | 3190 | |
Pancreas | 2005 | −0.0268*** | (0.0050) | −0.0494*** | (0.0103) | −0.0776*** | (0.0135) | −0.0586*** | (0.0133) | 696 | 7480 |
2006 | −0.0280*** | (0.0053) | −0.0372*** | (0.0105) | −0.0568*** | (0.0161) | −0.0632*** | (0.0112) | 702 | 8031 | |
2007 | −0.0280*** | (0.0051) | −0.0387*** | (0.0095) | −0.0503*** | (0.0150) | −0.0597*** | (0.0112) | 680 | 8854 | |
Stem cell | 2005 | 0.0033 | (0.0053) | 0.0123 | (0.0140) | 0.0044 | (0.0109) | −0.0011 | (0.0184) | 100 | 5489 |
2006 | 0.0042 | (0.0085) | 0.0383** | (0.0166) | 0.0043 | (0.0164) | 0.0139 | (0.0151) | 94 | 5883 | |
2007 | 0.0056 | (0.0059) | 0.0290** | (0.0130) | 0.0126 | (0.0139) | 0.0258* | (0.0134) | 100 | 5687 | |
Knee | 2005 | −0.0005*** | (0.0002) | −0.0002 | (0.0003) | −0.0006* | (0.0003) | 1047 | 115,401 | ||
2006 | −0.0007*** | (0.0002) | −0.0009*** | (0.0003) | −0.0012*** | (0.0003) | −0.0026*** | (0.0010) | 1008 | 122,150 | |
2007 | −0.0004*** | (0.0002) | −0.0003 | (0.0003) | −0.0006** | (0.0002) | −0.0005 | (0.0008) | 999 | 132,195 | |
CABG | 2005 | −0.0011 | (0.0046) | −0.0008 | (0.0086) | −0.0064 | (0.0078) | 0.0012 | (0.0105) | 94 | 30,633 |
2006 | −0.0009 | (0.0050) | 0.0004 | (0.0070) | −0.0037 | (0.0081) | −0.0021 | (0.0099) | 101 | 27,891 | |
2007 | −0.0103*** | (0.0037) | −0.0052 | (0.0055) | −0.0107* | (0.0061) | −0.0157* | (0.0094) | 98 | 27,644 | |