This release constitutes what we consider the minimum viable product for use by individual learners or by teachers in the classroom. The practice service has been live since April 2012 (with a total of about 4,000 users completing about 64,000 questions since then!), but the following new features make it a must-have for the discerning teacher and the keen student.
- A teachers' dashboard that shows the engagement and performance of the learners in their classes. If you're interested in how we use analytics to inform teachers where their students are succeeding or struggling, have a look at the teacher dashboard tour.
- A probabilistic model of users' mastery of questions, sections, chapters
and subjects allows the practice service to automatically adjust the
difficulty of questions being presented to the user, based on their level of mastery.
(If you're a Bayesian inference geek: The generative model is a hierarchical Gaussian prior over mastery scores with a binomial likelihood function and a logistic link function between the prior and likelihood. Inference is done with a fully factored variational approximation.)
- We now organise exercises using a section hierarchy rather than tags, allowing for better navigation and filtering from the teachers' and learners' dashboards. This also allows teachers and learners to drill down and select questions at the section rather than the chapter level.
- Navigation on mobile phones is functional. The www interface is still much prettier, but we're working on making mobi better every day. Making the practice service as accessible as possible over mobile phones is a huge priority for us since more than two thirds of our traffic comes from mobile devices. See our 2012 readership report for more information.
- Better Postgresql database migration for altering table structure.
- And, as always, some bugfixes.