This document discusses measuring and controlling variability in a core facility environment. It notes that increased variability decreases statistical power to detect real effects. Common sources of variability include biological differences, sample preparation inconsistencies, and technical issues. The document asks how best to communicate these issues to customers given limited funding to directly measure variability. It discusses challenges like analyzing samples over long periods when preparation methods may differ, having no control over initial sample collection, and potential sources of variability like pipetting errors. Finally, it provides an example method using pooled and individual samples to empirically measure variability introduced through sample processing.