R is for Archaeology: A report on the 2017 Society of American Archaeology meeting

by Ben Marwick, Associate Professor of Archaeology, University of Washington and Senior Research Scientist, University of Wollongong

The Society of American Archaeology (SAA) is one of the largest professional organisations for archaeologists in the world, and just concluded its annual meeting in Vancouver, BC at the end of March. The R language has been a part of this meeting for more than a decade, with occasional citations of R Core in the posters, and more recently, the distinctive ggplot2 graphics appearing infrequently on posters and slides. However, among the few archaeologists that have heard of R, it has a reputation for being difficult to learn and use, idiosyncratic, and only suitable for highly specialized analyses. Generally, archaeology students are raised on Excel and SPSS. This year, a few of us thought it was time to administer some first aid to R's reputation among archaeologists and generally broaden awareness of this wonderful tool. We developed a plan for this year's SAA meeting to show our colleagues that R is not too hard to learn, it is useful for almost anything that involves numbers, and it has lots of fun and cool people that use it to get their research done quicker and easier.

Our plan had three main elements. The first element was the début of two new SAA Interest Groups. The Open Science Interest Group (OSIG) was directly inspired by Andrew MacDonald's work founding the ESA Open Science section, with the OSIG being approved by the SAA Board this year. It aims to promote the use of preprints (e.g. SocArXiv), open data (e.g. tDAR, Open Context), and open methods (e.g. R and GitHub). The OSIG recently released a manifesto describing these aims in more detail. At this SAA meeting we also saw the first appearance of the Quantitative Archaeology Interest Group, which has a strong focus on supporting the use R for archaeological research. The appearance of these two groups shows the rest of the archaeological community that there is now a substantial group of R users among academic and professional archaeologists, and they are keen to get organised so they can more effectively help others who are learning R. Some of us in these interest groups were also participants in fora and discussants in sessions throughout the conference, and so had opportunities to tell our colleagues, for example, that it would be ideal if R scripts were available for for certain interesting new analytical methods, or that R code should be submitted when manuscripts are submitted for publication.

The second element of our plan was a normal conference session titled 'Archaeological Science Using R'. This was a two hour session of nine presentations by academic and professional archaeologists that were live code demonstrations of innovative uses of R to solve archaeological research problems. We collected R markdown files and data files from the presenters before the conference, and tested them extensively to ensure they'd work perfectly during the presentations. We also made a few editorial changes to speed things up a bit, for example using readr::read_csv instead of read.csv. We were told in advance by the conference organisers that we couldn't count on good internet access, so we also had to ensure that the code demos worked offline. On the day, the live-coding presentations went very well, with no-one crashing and burning, and some presenters even doing some off-script code improvisation to answer questions from the audience. At the start of the session we announced the release of our online book containing the full text of all contributions, including code, data and narrative text, which is online here. We could only do this thanks to the bookdown package, which allowed us to quickly combine the R markdown files into a single, easily readable website. I think this might be a new record for the time from an SAA conference session to a public release of an edited volume. The online book also uses Matthew Salganik's Open Review Toolkit to collect feedback while we're preparing this for publication as an edited volume by Springer (go ahead and leave us some feedback!). There was a lot of enthusiastic chatter later in the conference about a weird new kind of session where people were demoing R code instead of showing slides. We took this as an indicator of success, and received several requests for it to be a recurring event in future meetings.

The third element of our plan was a three hour training workshop during the conference to introduce archaeologists to R for data analysis and visualization. Using pedagogical techniques from Software Carpentry (i.e. sticky notes, live coding and lots of exercises), Matt Harris and I got people using RStudio (and discovering the miracle of tab-complete) and modern R packages such as readxl, dplyr, tidyr, ggplot2. At the end of three hours we found that our room wasn't booked for anything, so the students requested a further hour of Q&A, which lead to demonstrations of knitr, plotly, mapview, sf, some more advanced ggplot2, and a little git. Despite being located in the Vancouver Hilton, this was another low-bandwidth situation (which we were warned about in advance), so we loaded all the packages to the student's computers from USB sticks. In this case we downloaded package binaries for both Windows and OSX, put them on the USB sticks before the workshop, and had the students run a little bit of R code that used install.packages() to install the binaries to the .libpaths() location (for Windows) or untar'd the binaries to that location (for OSX). That worked perfectly, and seemed to be a very quick and lightweight method to get packages and their dependencies to all our students without using the internet. Getting the students started by running this bit of code was also a nice way to orient them to the RStudio layout, since they were seeing that for the first time.

This workshop was a first for the SAA, and was a huge success. Much of this is due to our sponsors who helped us pay for the venue hire (which was surprisingly expensive!). We got some major support from Microsoft Data Science User Group program (ed note: email msdsug@microsoft.com for info about the program) and Open Context, as well as cool stickers and swag for the students from RStudio, rOpenSci, and the Centre for Open Science. We used the stickers like tiny certificates of accomplishment, for example when our students produced their first plot, we handed out the ggplot2 stickers as a little reward.

Given the positive reception of our workshop, forum and interest groups, our feeling is that archaeologists are generally receptive to new tools for working with data, perhaps more so now than in the past (i.e. pre-tidyverse). Younger researchers seem especially motivated to learn R because they may have heard of it, but not had a chance to learn it because their degree program doesn't offer it. If you are a researcher in a field where R (or any programming language) is only rarely used by your colleagues, now might be a good time to organise a rehabilitation of R's reputation in your field. Our strategy of interest groups, code demos in a conference session, and a short training workshop during the meeting is one that we would recommend, and we imagine will transfer easily to many other disciplines. We're happy to share more details with anyone who wants to try!