ICCDesign: Intraclass Correlation Coefficient (ICC) Design, Calculation and Interactive 'shiny' Toolkit

A comprehensive toolkit for intraclass correlation coefficient (ICC) analysis, integrating three core functionalities: (1) Closed-form sample size calculation for ICC estimation with assurance probability, based on Zou (2012) ; (2) Full implementation of all 10 ICC types (6 common + 4 supplementary) for point estimation, exact confidence interval calculation, and formal hypothesis testing, following the methods of McGraw & Wong (1996) and the standard decision framework; (3) An interactive 'shiny' application that guides users through ICC type selection, performs calculations, and provides reliability evaluation based on the Koo & Li (2016) criteria. Compared to existing packages, it provides a unified decision workflow and supports all less common ICC variants.