Metrics and data are more abundant than ever in the field of design. Access to parametric analysis tools, micro-climate weather files, 15-minute increment submetering reports, and aggregated post-occupancy evaluations now often influence an architect’s approach. We are now frequently called on to understand, evaluate, and respond to an ever-growing mass of data. Which data are essential and meaningful to inform our work? What is the scale of influence of these numbers, and what role can and should they play in our process?