IrtRuby is a Ruby library for Item Response Theory (IRT) analysis, commonly used in educational assessment, psychological testing, and survey research. Features three core IRT models: • Rasch Model (1PL) - Simple difficulty-only model • Two-Parameter Model (2PL) - Adds item discrimination • Three-Parameter Model (3PL) - Includes guessing parameter Key capabilities: • Joint maximum likelihood by gradient ascent with an adaptive learning rate • Convergence reporting, scale identification, and exclusion of extreme response patterns • Missing data strategies (ignore, treat as incorrect/correct) • Performance and convergence benchmark scripts Intended for researchers, data scientists, and developers working with educational assessments, psychological measurements, or any binary response data where item and person parameters need to be estimated simultaneously.