The current codes do not allow differentiation between minimally invasive glaucoma surgery (MIGS) and non-MIGS activity. In the development of each national tariff, NHS England and NHS Improvement undertakes an overall assessment of the impact of proposals. This includes consideration of change in expenditure on different types of care in ‘2019/20 National Tariff Payment System – A consultation notice: Impact assessment’. While this provides an overall assessment of impact, detailed feedback on proposed prices for individual Healthcare Resource Groups (units of healthcare) is sought from clinical Expert Working Groups (EWGs). EWGs are managed by the NHS Digital National Casemix Office and comprise clinicians representing specific specialities. This is to ensure that the published tariff supports clinical practice.