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Table 4 Summary of coefficients and incident rate ratios (IRR)

From: Predicting length of stay from an electronic patient record system: a primary total knee replacement example

  Coefficient Std. error z value Pr (>|z|) Significance IRR
(Intercept) 3.51500 0.32630 10.772 <2e-16 *** 33.62
Admission.Year.Group2011 -0.0999 0.03409 -2.930 0.00339 ** 0.90
Age.at.Admission -0.04659 0.00933 -4.996 0.00000 *** 0.95
Age.Squared 0.00043 0.00007 6.160 0.00000 *** 1.00
GenderMale -0.13760 0.02525 -5.450 0.00000 *** 0.87
Consultant.Pseudo.Code.PK.GroupC38 0.07489 0.05752 1.302 0.19292   1.08
Consultant.Pseudo.Code.PK.GroupC42 0.11630 0.05977 1.946 0.05164 . 1.12
Consultant.Pseudo.Code.PK.GroupC46 0.13800 0.06180 2.234 0.02551 * 1.15
Consultant.Pseudo.Code.PK.GroupC49 0.01046 0.05734 0.182 0.85523   1.01
Consultant.Pseudo.Code.PK.GroupC58 0.06061 0.05859 1.034 0.30093   1.06
Consultant.Pseudo.Code.PK.GroupC59 -0.07585 0.06385 -1.188 0.23481   0.93
Consultant.Pseudo.Code.PK.GroupC62 0.17290 0.06781 2.550 0.01077 * 1.19
Consultant.Pseudo.Code.PK.GroupC64 0.03859 0.06718 0.574 0.56574   1.04
Consultant.Pseudo.Code.PK.GroupOther consultant 0.12170 0.05685 2.142 0.03223 * 1.13
Admission.DayMonday -0.01045 0.04263 -0.245 0.80631   0.99
Admission.DaySaturday -0.16110 0.04504 -3.578 0.00035 *** 0.85
Admission.DaySunday 0.45220 0.07280 6.211 0.00000 *** 1.57
Admission.DayThursday 0.00404 0.04522 0.089 0.92877   1.00
Admission.DayTuesday 0.10370 0.05123 2.024 0.04300 * 1.11
Admission.DayWednesday 0.01796 0.04357 0.412 0.68018   1.02
Discharge.Destination.PK.GroupOther discharge dest 0.10560 0.11270 0.937 0.34855   1.11
Discharge.Destination.PK.GroupUsual place of resid -0.32660 0.05522 -5.915 0.00000 *** 0.72
Rank.of.IMD.Score -0.000005 0.00000 -2.901 0.00372 ** 1.00
Ethnicity.Common.GroupWhite, declined and unknown - 0.13000 0.07777 -1.671 0.09467 . 0.88
  1. 0 = ‘***’ : 0.001 = ‘**’ : 0.01 = ‘*’ 0.05 : ‘.’ = 0.1 : ‘ ’ = 1.