This resource explains why data collection is a great way to make informed improvements to a design, and how to do it. Data can be quantitative - such as a measurement of distance or time - or qualitative, such as an observation of performance. During testing, teams observe how the design performs and record measurements, written descriptions of the outcome, and new ideas through sketches. Adding measurements to design challenges that indicate success or failure can motivate learners with incremental victories and enrich the experience. For example, add an accelerometer to an egg drop activity, or look at the speed of a vehicle rather than just whether it crossed a finish line.