Data analysis involves a large amount of janitor work - munging and cleaning data to facilitate downstream data analysis. This workshop is designed for those with a basic familiarity with R who want to learn tools and techniques for advanced data manipulation. It will cover data cleaning and "tidy data," and will introduce participants to R packages that enable data manipulation, analysis, and visualization using split-apply-combine strategies. Upon completing this lesson, participants will be able to use the dplyr package in R to effectively manipulate and conditionally compute summary statistics over subsets of a "big" dataset containing many observations.