To measure surface roughness, a roughness gage (sometimes called a stylus profilometer) traces a small stylus over the surface. A stylus on its own can be very sensitive to not only the surface but also to outside influences. Any vibration or disturbance can make it move, which will introduce errors to the measurement. To help solve this issue, a stylus is often housed within a skidded probe. But a skid can cause other measurement errors as well. In this Notepad Series video, we describe how a skid works, how it can help improve your data, and how some potential pitfalls can adversely affect your surface roughness measurements.