If we want to make data-driven decisions, we need data. Currently, you may be gathering informal data by having your students hold up X number of fingers to express their level of understanding. They may add a colored sticky note to chart paper to show you to stop and re-teach (red), full steam ahead (green), or to slow down (yellow). You may start the class with a bell ringer that tells you what they learned from watching the video the night before. Or you may ask them to write what they got out of today's class on an index card. What do you do with that data? How do you analyze it?
Digital tools are wonderful to assess FOR learning, while having access the data immediately - and, often, an a way that allows students to comment on the data or see it as a graph.
What are your favorites?