454-455 / 1676
NTCP-models
External validation
•
Different levels of adjustment (calibration-in-the-large,
calibration of intercept and slope, model revision)
–
Closed testing procedure
•
Model extension:
–
Add new predictors to an existing model
•
Model adjustment / revision can still be considered as
external validation, although the level of adjustment
determines how
new
the model is
Linear predictor:
LP = +
1
X
1
+
2
X
2
LP = +
1
X
1
+
2
X
2
+
3new
X
3new
Vergouwe, et al. Stat Med 2017