Quantitative Methods 2017

Closed testing procedure External validation dysphagia grade II-IV

Validation cohort (n=354)

Model extension (n=813)

Recalibrated intercept and slope

Model

Original model Recalibration in-the-large

Revision

Model parameters Intercept

-6.089

-5.727

-4.556 0.772 0.044 0.028

-3.714

-3.303

Overall slope *

D mean superior PCM D mean supraglottic area

0.057 0.037

0.057 0.037

0.061 -0.003

0.024

D mean oral cavity

0.024

Baseline dysphagia (grade 2-3 versus grade 0-1)

0.967

Model performance C-statistic

0.74

0.74

0.74

0.77

0.81

Expected NTCP Observed NTCP

24.7% 30.8% 30.8% 30.8% 29.8% 30.8% 30.8% 30.8% 30.8% 29.8%

Hosmer-Lemeshow test

P<0.001

P=0.019

P=0.118

P=0.368

P=0.042

Intercept

0.146 0.772

-0.134 0.772

0.000 1.000

0.000 1.000

0.120 1.090

Slope