A new dashboard ranks more than 100 federal agencies based on their use of Twitter. The Federal Social Media Index, created by nonprofit ExpertLabs, tracks how agencies are engaging their public based on several measures. For the week ending December 4, NASA came out on top, with 360 replies from 1,643,429 followers. (Most answered question: “Ever watch the space station fly over your house?”) But number of followers isn’t the only criterion. The Navy, for instance, has a 133% question-to-response ratio with its 38,000 followers while the Federal Communications Commission didn’t ask a single question of its 452,000 followers. Dashboard developer Andy Baio told Nextgov that the site has plans to add additional metrics in the future, including a measure of how agencies respond to questions from their followers, how active agencies are under particular Twitter lists and hash tags, and word and tone analysis to assess responses to positive and negative tweets. Future versions will measure agency engagement on Facebook and other social media platforms. Link to full story in Nextgov. Link to TheTransitWire.com.