The data used in the visualization above originates from another project I am involved with called FlourishOA.org. The FlourishOA team collects and analyzes data about Open Access publications. Much of this data is publicly accessible through the FlourishOA.org API.
The three variables charted above are:
The bar chart is designed to give you summary information about the mean APC to publish in Open Access journals in various fields (categories). The cost represented is a mean value for all years combined, or a particular year chosen from the drop-down menu. The default sorting is alphabetical by category, but the checkbox provided allows you to sort by descending mean APC.