DATA DIVING: Knewton CEO Jose Ferreira often talks big when it comes to Big Data, so it's fitting that he offers a breakdown of the 5 types of educational data that matter to his company. Three of them--identity (personal data), system-wide (roster, attendance), and user interaction (for online programs)--and fairly straightforward. Then there's also "inferred content data," which focuses on the efficacy of instructional materials for different groups of students, and "inferred student data," which tries to measure student proficiency and the factors affecting it. Most educators, he says, take action based solely on user interaction data without the inferred data pieces. Never one to be humble, he writes, "To our knowledge, we're the only ones out there doing it." Others may beg to differ.