Metal additive manufacturing is only as reliable as our ability to see what happens in the melt pool and to quantify our confidence in each part. We use infrared thermography and synchronized in-situ measurements to monitor laser powder bed fusion of alloys such as 316L stainless steel and IN718. We have also developed methods to measure the emissivity of metal powders, so thermal images can be converted into accurate temperatures. Building on metrology principles, we apply statistical quality assessment and measurement-uncertainty analysis to judge whether a process is in control. We also study how factors such as powder particle size affect build quality. For directed energy deposition, we model the process dynamics to understand how disturbances affect part geometry.