A package with one function: icc_type_i. icc_type_i uses a user-provided ICC and sample size to calculate the expected Type-I Error rate resulting from a multi-level model treated as a single-level model. The function was inspired by Musca, Kamiejski, Nugier, Méot, Er-Rafiy, and Brauer's (2018) "Data with hierarchical structure: Impact of intraclass correlation and sample size on Type-I error" and makes use of much of the code found in the appendix of said paper.