Article 312 1 (a) sets a minimum frequency of once every 3 years for the full RSR. Article 307 of the Delegated Act requires a comparison, in the RSR, of the current reporting period's performance with the reported in the previous reporting period. Pursuant to Article 312 (3) (re)insurance undertakings need to submit summary RSR for the reporting periods with material changes when no full RSR is due. Thereafter the previous reporting period is considered the period for which material change was reported or in case of no material change reported, the previous reporting period is the one for which full RSR was submitted.

In the particular example provided in the question the reference should be made to the 2018 as a previous reporting period (which is the period for which summary RSR was submitted with material changes on underwriting performance and not to the full RSR provided in 2016).