Rex: R-linked EXcel add-in for statistical analysis of medical and bioinformatics data.

Background: Microsoft Excel has substantial functionalities for data management and analyses, and has been the most popular software in this field. However, in spite of Excel's user-friendly interface and functionality for data management, it provides very few functions for in-depth statistical analyses, which has limited its wider application for this purpose.

Objective: Here, we introduce Rex, an Excel add-in software implementing the powerful analytical and graphical functions of R within Excel.

Methods: Rex was implemented using three types of programming software: R, JavaScript, and Microsoft VB.Net.

Results: Rex provides a graphical user interface (GUI) through Excel, and statistical analysis can be conducted by pointing and clicking the menu without programming R. Rex covers a wide range of analyses from basic statistics to advanced analysis, including structural equation modeling, complex sampling design, and machine learning models, making it possible for researchers not skilled in using a command-line interface to conduct in-depth statistical analyses. Most Rex modules are available in a free version for non-commercial use, and it can be used for educational and public purposes.

Conclusion: In this article, we introduce the framework and features of Rex with illustrative examples of its implementation.