Secessionist Movements, version 3. Identifies 403 secessionist movements between 1816 and 2011. Please cite my 2015 article in International Organization. (data)

Proto-States, version 3. Identifies 638 proto-states between 1816 and 2011. Please cite my 2015 article in International Organization. (data)

International System(s) Dataset (ISD), version 1. Identifies 363 sovereign states between 1816 and 2011. Please cite my 2013 co-authored article in International Interactions. (data); (code book)