This project contains data and code relating to Ostwald et al. (2021) 'Random field theory-based p-values: a review of the SPM implementation'. - The .m files rft_1.m to rft_6.m implement simulations and visualizations as referenced in the respective Figure captions of Ostwald et al. (2021) 'Random field theory-based p-values: a review of the SPM implementation'. For details, please refer to the function headers. - The .m files rft_spm_est_smoothness.m and rft_spm_results_table.m are simplified and documented revisions of the central SPM functions spm_est_smoothness.m, spm_list.m, and spm_P_RF.m that implement the evaluation of random field theory-based p-values in SPM. - The SPM.zip file contains the SPM12 Version 7771 distribution the RFT implementation of which is documented in the manuscript. - The 'Data' folder contains the files Contrast Images.zip and One Sample T Test.zip. These comprise the contrast images analyzed with a second-level one-sample T-test design for Figure 1 of the manuscript, and the results of this analysis, respectively.