File stimuli_RAT_RUS.csv contains 100 Russian language RAT problems and data on accuracy, error types, after-generation after-presentation Aha judgements, confidence judgements, subjective difficulty judgements, and likability judgements. Descriptions of the vriables are provided in the "metadata_rat_rus_stimuli.txt". File RAT_data_full.csv is the full dataset obtained in the research. Descriptions of the vriables are provided in the "meta_data_full.txt". File "aha_experience_(rus).docx" contains a description of Aha! experience in Russian. You can use them or modify the data as you wish as long as you cite the original paper (see licence.txt). Citation: Moroshkina NV, Savina AI, Ammalainen AV, Gershkovich VA, Zverev IV and Lvova OV (2022) How Difficult Was It? Metacognitive Judgments About Problems and Their Solutions After the Aha Moment. Front. Psychol. 13:911904. doi: 10.3389/fpsyg.2022.911904 If you have any questions or commentaries, please feel free to contact us at alinasavn@gmail.com (Alina Savina).