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@ARTICLE{Ooi:1044428,
      author       = {Ooi, Leon Qi Rong and Orban, Csaba and Zhang, Shaoshi and
                      Nichols, Thomas E. and Tan, Trevor Wei Kiat and Kong, Ru and
                      Marek, Scott and Dosenbach, Nico U. F. and Laumann, Timothy
                      O. and Gordon, Evan M. and Yap, Kwong Hsia and Ji, Fang and
                      Chong, Joanna Su Xian and Chen, Christopher and An, Lijun
                      and Franzmeier, Nicolai and Roemer-Cassiano, Sebastian N.
                      and Hu, Qingyu and Ren, Jianxun and Liu, Hesheng and Chopra,
                      Sidhant and Cocuzza, Carrisa V. and Baker, Justin T. and
                      Zhou, Juan Helen and Bzdok, Danilo and Eickhoff, Simon B.
                      and Holmes, Avram J. and Yeo, B. T. Thomas and Jack,
                      Clifford R.},
      title        = {{L}onger scans boost prediction and cut costs in brain-wide
                      association studies},
      journal      = {Nature},
      volume       = {644},
      issn         = {0028-0836},
      address      = {London [u.a.]},
      publisher    = {Nature Publ. Group},
      reportid     = {FZJ-2025-03189},
      pages        = {731–740},
      year         = {2025},
      abstract     = {A pervasive dilemma in brain-wide association studies1
                      (BWAS) is whether to prioritize functional magnetic
                      resonance imaging (fMRI) scan time or sample size. We derive
                      a theoretical model showing that individual-level phenotypic
                      prediction accuracy increases with sample size and total
                      scan duration (sample size × scan time per
                      participant). The model explains empirical prediction
                      accuracies well across 76 phenotypes from nine resting-fMRI
                      and task-fMRI datasets (R2 = 0.89), spanning diverse
                      scanners, acquisitions, racial groups, disorders and ages.
                      For scans of ≤20 min, accuracy increases linearly with
                      the logarithm of the total scan duration, suggesting that
                      sample size and scan time are initially interchangeable.
                      However, sample size is ultimately more important.
                      Nevertheless, when accounting for the overhead costs of each
                      participant (such as recruitment), longer scans can be
                      substantially cheaper than larger sample size for improving
                      prediction performance. To achieve high prediction
                      performance, 10 min scans are cost inefficient. In most
                      scenarios, the optimal scan time is at least 20 min. On
                      average, 30 min scans are the most cost-effective,
                      yielding $22\%$ savings over 10 min scans. Overshooting
                      the optimal scan time is cheaper than undershooting it, so
                      we recommend a scan time of at least 30 min. Compared with
                      resting-state whole-brain BWAS, the most cost-effective scan
                      time is shorter for task-fMRI and longer for
                      subcortical-to-whole-brain BWAS. In contrast to standard
                      power calculations, our results suggest that jointly
                      optimizing sample size and scan time can boost prediction
                      accuracy while cutting costs. Our empirical reference is
                      available online for future study design
                      (https://thomasyeolab.github.io/OptimalScanTimeCalculator/index.html).},
      cin          = {INM-7},
      ddc          = {500},
      cid          = {I:(DE-Juel1)INM-7-20090406},
      pnm          = {5251 - Multilevel Brain Organization and Variability
                      (POF4-525)},
      pid          = {G:(DE-HGF)POF4-5251},
      typ          = {PUB:(DE-HGF)16},
      doi          = {10.1038/s41586-025-09250-1},
      url          = {https://juser.fz-juelich.de/record/1044428},
}