This package provides functions for working with two- and four-parameter Beta distributions and the closely related Beta-Binomial distribution, and for estimating the accuracy and consistency of test-based classifications. Includes d/p/q/r functions for four-parameter Beta distributions, including parameterization by mean and variance; d/p/r functions for Beta-Binomial distributions and for Lord's two-term approximation to the compound Binomial distribution; moments of Beta, Binomial, Beta-Binomial, and observed-score distributions; and method-of-moments fitting of two- and four-parameter Beta true-score distributions. Classification accuracy and consistency can be estimated with the Livingston and Lewis approach (Livingston and Lewis, 1995 <doi:10.1111/j.1745-3984.1995.tb00462.x>), the Hanson and Brennan approach based on Lord's strong true-score theory (Lord, 1965 <doi:10.1007/BF02289490>; Hanson, 1991 <https://files.eric.ed.gov/fulltext/ED344945.pdf>), and the multinomial and compound multinomial approach (Lee, 2007 <doi:10.1177/0146621606294206>; Lee, Brennan, and Wan, 2009 <doi:10.1177/0146621608321759>), for two or more categories, with ROC analysis, model-fit tests, and examinee- or score-level results.