If you are interested in studying the history of VAST you're pretty safe just using the conference name column. If you are interested in studying the history of InfoVis - you're more or less safe depending on what you're interested in. If you're interested in a completeness of papers and go by the conference name column alone, you may miss a few papers that are among the VIS papers (maybe a handful a year). If you would like to track them down you could go into the proceedings and find the respective InfoVis sessions and mark those papers as InfoVis-related in the dataset (feel free to send us your data updates for inclusion here). If you're interested in the evolution of SciVis you now have to use a combination of Vis and SciVis conference names but beware that you will be including a few papers that nowadays people would put into InfoVis or VAST category.
In order to give a more correct reflection of the historical evolution of the field we decided to introduce "Vis" back into the conference names column for all papers that met the following criteria: conference name = SciVis, year <= 2012. This better reflects the following:What does this mean for you?
There was only one conference in the beginning. This conference was called Vis. It included a wide variety of papers, including what some would call InfoVis or VAST today. Even with the foundation of the InfoVis symposium, in the beginning it was considered more prestigious to send your best work to the "main" conference which was the Vis conference. This culture changed only later but even in the early 2000's there were InfoVis sessions at the VIS conference.