With the aim of showing the structural changes in economy an updated National Classification of Economic Activities is established, named from now on CNAE09 which, since 2009 replaces the previous one, CNAE93 Rev.1. This classification allows enterprises, financial organizations and governments to have at their disposal comparable and reliable data.The transition to that new classification requires the producers of official statistics to adapt their statistical systems before implementing the new classification. This paper tries to explain the procedure applied to adjust the estimations about Labour Costs to the new classification.

Keywords: Backcasting, Calibration, Post-stratified estimator, Stratified Random Sampling, National Classification of Economic Activities, Quarterly Labour Cost Survey.

AMS Subject classifications: 62P25, 62M10, 62D05.