False political information spreads far and fast across social media, with negative consequences for society. Individual users play a key role in sharing such material, extending its range through the phenomenon of organic reach. An online experiment tested the hypotheses that higher trust in the source of false information, and lower agreeableness of the person encountering it, would predict their likelihood of extending its reach. 172 participants saw real examples of disinformation stories that had been posted to social media, and rated their likelihood of sharing and interacting with it in other ways. Neither trust in the source nor agreeableness influenced organic reach. However, people lower in conscientiousness rated themselves as more likely to extend its reach, as did people who believed the stories more likely to be true. The documents included here comprise the stimuli used in the study; a dataset (SPSS format) with summary scores that underpin the analysis; a data dictionary describing the dataset; SPSS syntax for the main analysis; and the full questionnaire used for data collection (an unedited export from Qualtrics). This includes consent materials, and all combinations of the experimental stimuli (participants only saw one combination within one condition). Project was published as: Buchanan, T. (2021). Trust, personality, and belief as determinants of the organic reach of political disinformation on social media. The Social Science Journal, 1-12. https://doi.org/10.1080/03623319.2021.1975085