How the Census Bureau classifies political and statistical geographic entities

Here's the link to the video recording of a lecture that Michael Ratcliffe, Census Bureau, gave two years ago in a distance learning class organized by Cornell. The topic concerns how the Census Bureau classifies political and statistical geographic entities.

The first 1 hour and 25 minutes are Michael's presentation, and the remainder is second half of the class in which Lars Vilhuber, Cornell, deals with citations in scholarly work—especially citing data. If metadata is your thing you may want to view that lecture as well.