Census Map

Interactive map of the 2010 Census by the NYT.

Krosnik paper on panel quality

Stanford prof Jon Krosnik has conducted a stream of research on the data quality differences between probability (RDD) samples and non-probability (online panel) samples.  His findings are striking, and call into question the practice of using online panels so heavily in Marketing Research.

Background on the issue at ABC News, and links to his work.  Also, the seminal 2011 AAPOR report on the topic.