Elaine Kamarck, who spent the 1980s as an intellectual guru of the New Democrat tendency, has decided to do something useful. Now perched at the Brookings Institution, she runs the Primaries Project, which gathers systematic data on every major-party Congressional primary candidate across the country. Given the ephemeral nature of Congressional primary campaigns — which get little attention while they’re happening and evaporate into the ether as soon as they’re over — it’s a valuable service she’s performing.

Her latest update looks at the “progressives vs establishment” battle on the Democratic side and offers some potentially useful data. First, she and her collaborators classified all 681 non-incumbent Democratic primary candidates as either “progressive” or “establishment,” based on “how they self-identify ideologically.” (More on that in a moment.)