Digital tools are making it easier than ever for teachers to gather and analyze formative data. Paper exit slips can take a classroom teacher upward of an hour to sort and graph after just one day of classes. But now, that same teacher can pose a question out loud to the class and ask students to type answers on their mobile phones and hit send. Instantly, the educator knows which students understand and which do not. They can then apply last-minute lesson plans or homework assignment interventions on the fly.