A doctorate in Computer Science
My Ph.D. is in Computer Science. My dissertation built an adaptive learning system called SAILS, using Bayesian networks (a math method for updating a belief as new evidence arrives), Bloom’s Taxonomy (a way of ranking how deep a thinking skill is), the Felder-Soloman Learning Style Index, and self-efficacy tracking (measuring how capable a learner believes they are).
Writing the software was never the hard part. The hard part was justifying every single claim that system made about a learner. That is the same question a district faces the first time a parent pushes back on a score.