IEC TS 61400-26-2:2014 provides a framework from which production-based performance indicators of a wind turbine generator system can be derived. It unambiguously describes how data is categorised and provides examples of how the data can be used to derive performance indicators. The approach of this part of IEC 61400 is to expand the time allocation model, introduced in IEC TS 61400-26-1, with two additional layers for recording of the actual energy production and potential energy production associated with the concurrent time allocation. This document also includes informative annexes with: - examples of determination of lost production, - examples of algorithms for production-based indicators, - examples of other performance indicators, - examples of application scenarios.