Journal Article

FZJ-2021-02221

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Systematic misestimation of machine learning performance in neuroimaging studies of depression

Flint, C. ; Cearns, M. ; Opel, N. ; Redlich, R. ; Mehler, D. M. A. ; Emden, D. ; Winter, N. R. ; Leenings, R. ; Eickhoff, S. B.FZJ* ; Kircher, T. ; Krug, A. ; Nenadic, I. ; Arolt, V. ; Clark, S. ; Baune, B. T. ; Jiang, X. ; Dannlowski, U. (Corresponding author) ; Hahn, T.

2021
Nature Publishing Group Basingstoke

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Please use a persistent id in citations: http://hdl.handle.net/2128/28282  doi:10.1038/s41386-021-01020-7

Abstract: We currently observe a disconcerting phenomenon in machine learning studies in psychiatry: While we would expect larger samples to yield better results due to the availability of more data, larger machine learning studies consistently show much weaker performance than the numerous small-scale studies. Here, we systematically investigated this effect focusing on one of the most heavily studied questions in the field, namely the classification of patients suffering from Major Depressive Disorder (MDD) and healthy controls based on neuroimaging data. Drawing upon structural MRI data from a balanced sample of N = 1868 MDD patients and healthy controls from our recent international Predictive Analytics Competition (PAC), we first trained and tested a classification model on the full dataset which yielded an accuracy of 61%. Next, we mimicked the process by which researchers would draw samples of various sizes (N = 4 to N = 150) from the population and showed a strong risk of misestimation. Specifically, for small sample sizes (N = 20), we observe accuracies of up to 95%. For medium sample sizes (N = 100) accuracies up to 75% were found. Importantly, further investigation showed that sufficiently large test sets effectively protect against performance misestimation whereas larger datasets per se do not. While these results question the validity of a substantial part of the current literature, we outline the relatively low-cost remedy of larger test sets, which is readily available in most cases.

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Contributing Institute(s):

1. Gehirn & Verhalten (INM-7)

Research Program(s):

1. 525 - Decoding Brain Organization and Dysfunction (POF4-525) (POF4-525)

Appears in the scientific report 2021

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Database coverage:
; ; ; BIOSIS Previews ; Current Contents - Life Sciences ; Ebsco Academic Search ; IF >= 5 ; JCR ; NCBI Molecular Biology Database ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Thomson Reuters Master Journal List ; Web of Science Core Collection

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