Mismatch loss relating to difference in as-manufactured cell performance is known to be nearly non-existent in a modern, undamaged, photovoltaic module. At a system level, potential contributors to this loss can include manufacturing variance, uncertainties in cell and module performance measurements and variation in operating conditions in the field. While some of these aspects have been individually studied, often using idealised performance models, there lacks a holistic treatment that assesses all the contributing effects in the same context. This is particularly important given the potential for trade-off among some of the underlying loss mechanisms in the way cells and modules are grouped and installed. This study shows, using a hybridised approach of published studies, manufacturing data, field performance data, and performance and variance modeling, that mismatch loss remains a potentially important performance loss mechanism in many photovoltaic installation. The decisions made in manufacturing pertaining to mismatch loss are found to often have only a small impact, despite potentially adding cost and complexity to the process. Conversely, field installation issues are shown to be of dominant importance in the final mismatch loss estimate. Understanding the individual contributing mechanisms, all together, will allow for the development of a realistic and least cost approach to mitigating the loss right from the decisions made in manufacturing through to how the modules are installed in the field.