. 2021 Nov 17;23(11):e30042. doi: 10.2196/30042
©Andreas Knapp, Lorenz Harst, Stefan Hager, Jochen Schmitt, Madlen Scheibe. Originally published in the Journal of Medical Internet Research (https://www.jmir.org), 17.11.2021.
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Figure 6.
Numbers of studies by study type over time. RCT: randomized controlled trial.