Hadley Alexander Wickham (born 14 October 1979) is a New Zealand statistician known for his work on open-source software for the R statistical programming environment. He is the chief scientist at Posit, PBC and an adjunct professor of statistics at the University of Auckland, Stanford University, and Rice University. His work includes the data visualisation system ggplot2 and the tidyverse, a collection of R packages for data science based on the concept of tidy data.

Wickham was born in Hamilton, New Zealand. He received a Bachelors degree in Human Biology and a masters degree in statistics at the University of Auckland in 1999–2004 and his PhD at Iowa State University in 2008 supervised by Di Cook and Heike Hofmann.^[3][4] He is the chief scientist at Posit, PBC (formerly RStudio)^[5] and an adjunct professor of statistics at the University of Auckland, Stanford University, and Rice University.^[6][7][8]

Wickham is a prominent and active member of the R user community and has developed several notable and widely used packages including ggplot2, plyr, dplyr and reshape2.^[8][9] Wickham's data analysis packages for R are collectively known as the tidyverse.^[10] According to Wickham's tidy data approach, each variable should be a column, each observation should be a row, and each type of observational unit should be a table.^[11]

Wickham's sister Charlotte Wickham is also a statistician.^[15]

Wickham's publications^[2] include:

• Wickham, Hadley; Grolemund, Garrett (2017). R for Data Science : Import, Tidy, Transform, Visualize, and Model Data. Sebastopol, CA: O'Reilly Media. ISBN 978-1491910399. OCLC 968213225.
• Wickham, Hadley (2015). R Packages. Sebastopol, CA: O'Reilly Media, Inc. ISBN 978-1491910597.
• Wickham, Hadley (2014). Advanced R. New York: Chapman & Hall/CRC The R Series. ISBN 978-1466586963.
• Wickham, Hadley (2011). "The split-apply-combine strategy for data analysis". Journal of Statistical Software. 40 (1): 1–29. doi:10.18637/jss.v040.i01.
• Wickham, Hadley (2010). "A layered grammar of graphics". Journal of Computational and Graphical Statistics. 19 (1): 3–28. doi:10.1198/jcgs.2009.07098. S2CID 58971746.
• Wickham, Hadley (2010). "stringr: modern, consistent string processing". The R Journal. 2 (2): 3–28. doi:10.32614/RJ-2010-012.
• Wickham, Hadley (2009). ggplot2: Elegant Graphics for Data Analysis (Use R!). New York: Springer. ISBN 978-0387981406.^[1]
• Wickham, Hadley (2007). "Reshaping data with the reshape package". Journal of Statistical Software. 21 (12): 1–20. doi:10.18637/jss.v021.i12.