How Human Factors Files Fail Medical Device Design and What Fixes Them

A human factors practitioner at a mid-sized medical device company has outlined the most common ways usability files fail Class II product development, based on direct audit and review experience. Key failure points include starting human factors work too late, shallow user profiling, abstract task analysis, and poor linkage between usability findings and ISO 14971 risk management records. The author argues that a poorly constructed usability file — even a lengthy one — cannot adequately demonstrate real-world device safety under IEC 62366-1 and FDA Human Factors Guidance. Practical remedies proposed include embedding human factors inputs at the requirements stage, recruiting representative users early, and treating usability findings through the same root cause analysis process used for CAPAs. The piece also stresses that post-market complaints and corrective actions should feed back into the usability file to close the loop on ongoing safety evidence.