Title
Cross-study validation for the assessment of prediction algorithms.
Abstract
Motivation: Numerous competing algorithms for prediction in high-dimensional settings have been developed in the statistical and machine-learning literature. Learning algorithms and the prediction models they generate are typically evaluated on the basis of cross-validation error estimates in a few exemplary datasets. However, in most applications, the ultimate goal of prediction modeling is to provide accurate predictions for independent samples obtained in different settings. Cross-validation within exemplary datasets may not adequately reflect performance in the broader application context. Methods: We develop and implement a systematic approach to 'cross-study validation', to replace or supplement conventional cross-validation when evaluating high-dimensional prediction models in independent datasets. We illustrate it via simulations and in a collection of eight estrogen-receptor positive breast cancer microarray gene-expression datasets, where the objective is predicting distant metastasis-free survival (DMFS). We computed the C-index for all pairwise combinations of training and validation datasets. We evaluate several alternatives for summarizing the pairwise validation statistics, and compare these to conventional cross-validation. Results: Our data-driven simulations and our application to survival prediction with eight breast cancer microarray datasets, suggest that standard cross-validation produces inflated discrimination accuracy for all algorithms considered, when compared to cross-study validation. Furthermore, the ranking of learning algorithms differs, suggesting that algorithms performing best in cross-validation may be suboptimal when evaluated through independent validation.
Year
DOI
Venue
2014
10.1093/bioinformatics/btu279
BIOINFORMATICS
Keywords
Field
DocType
algorithms,artificial intelligence,gene expression profiling
Data mining,Pairwise comparison,Ranking,Computer science,Prediction algorithms,Predictive modelling,Bioinformatics,Application Context
Journal
Volume
Issue
ISSN
30
12
1367-4803
Citations 
PageRank 
References 
5
0.49
14
Authors
7
Name
Order
Citations
PageRank
Christoph Bernau170.87
Markus Riester2253.04
Anne-Laure Boulesteix394563.22
Giovanni Parmigiani417412.46
Curtis Huttenhower543830.18
Levi Waldron6516.96
Lorenzo Trippa771.00