Volume: according to big data standards, the amount of raw data they had, was small. They had under 10 TB to start with, but because they led their analysts pursue their data-driven ideas they created a tenfold of this in a short time frame.
Variety: there were many sources of data; much of it was new to the DNC. Because of the short time span, they did not have time to build ETL processes to bring it all together nicely.
Velocity, the data analysts, staff and volunteers created new data at high-speed and that needed to be taken care of.