When patients take part in HTA, their knowledge gained from living with a condition and using treatments and services can add value to an HTA.[17] Sometimes they are called experience-based experts or lay experts.[18] Patients can add value to HTAs by providing real world insights (e.g. implications of benefits and side effects, variation in clinical practice)[19] highlighting outcomes that matter, addressing gaps and uncertainties in the published literature,[20][21] and contributing to the value construct that shapes assessments and decisions.[18]