This is the full dataset and accompanying codebook for the study "Demonstration of a ‘leapfrog’ randomized controlled trial as a method to accelerate the development and optimization of psychological interventions", published in Psychological Medicine (https://doi.org/10.1017/S0033291722003294). It supplements the partial dataset openly available on the Open Science Framework (https://osf.io/8mxda/) by also including further variables for which Sharing Level 1 was judged appropriate.

leapfrogdata2022-04-22.xlsx: Full dataset for the study; leapfrogdata2022-04-22.csv: .csv version of the database; Leapfrog Codebook 07.07.23.pdf: Codebook describing leapfrogdata