title: Simple adaptations to the Templeton model for IVF outcome prediction make it current and clinically useful.
abstract: OBJECTIVE
  What is the validity of the Templeton model (TM) in predicting live birth (LB) for a couple starting an IVF/ICSI cycle?
  
  
  CONCLUSIONS
  A centre-specific model based on the original predictors of the TM may reach a sufficient level of accuracy to be used in every day practice, with a few simple adaptations.
  
  
  BACKGROUND
  The TM seems the best predictive model of LB in IVF. However, previous validations of the TM suggest a lack of discrimination and calibration which means that it is not used in regular practice. We confirm this finding, and argue that such results are predictable, and essentially due to a strong centre effect. We provide evidence that the TM constitutes a useful reference reflecting a high proportion of the patient-mix effect since the parameters of the model remain invariant among centres, but also across various cultures, countries and types of hospitals. The only difference was the intercept value, interpreted as the measurement of the global performance of one centre, in particular, for a population of reference.
  
  
  METHODS
  The validity of the TM was tested by a retrospective analysis all IVF/ICSI cycles (n = 12 901) in our centre since 2000.
  
  
  METHODS
  All IVF/ICSI cycles were included in the analysis. The model discrimination was evaluated by C-statistics, calculated as the area under the curve of an ROC curve. The TM was then adjusted for our data and additional variables were assessed.
  
  
  RESULTS
  Poor calibration and discrimination (C = 0.64) was observed in conformity with previous external validations. Fitting the TM to our centre constituted the first substantial improvement in prediction accuracy of discrimination (C = 0.69) and calibration. We identified an important linear time trend effect and the added value of three other predictors (FSH, smoking habits and BMI) that significantly improved the model (C = 0.71).
  
  
  CONCLUSIONS
  Bias due to missing data handling was assessed through sensitivity analyses.
  
  
  CONCLUSIONS
  Neither the TM nor any other models based on some centres are directly applicable to other centres. However, the TM constitutes a useful basis to build an accurate centre-specific model.
  
  
  BACKGROUND
  There were no commercial relationships (i.e. consultancies, patent-licensing agreements) that might pose a conflict of interest in connection with the submitted manuscript. The objective of this research was not directed toward any treatment effects.
authors.affiliation: Clinique la Sagesse, Place St Guénolé, Rennes 35000, France. philippe.lehert@gmail.com
authors.forename: P
authors.initials: P
authors.lastname: Arvis
authors.forename: P
authors.initials: P
authors.lastname: Lehert
authors.forename: A
authors.initials: A
authors.lastname: Guivarc'h-Levêque
mesh_terms: D000328:Adult; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D007246:Infertility / Q000628:therapy*; D008962:Models, Theoretical; D012372:ROC Curve; D012189:Retrospective Studies; D016896:Treatment Outcome