Coverage and comparability of the datasets over time 

CCB and FEFCO have regularly surveyed the environmental performance of the corrugated industry for more than 27 years. This is the eleventh edition of the report. Inevitably, over time the coverage of the surveys has changed:
• Old paper mills and converting facilities have closed and new mills and converting facilities have opened
• Additional mills and converting facilities have opted to participate in the survey, increasing the coverage and representativeness of the datasets
Over the years there has been increased participation in the survey, which means that the weighted averages generated are more representative of average European production and therefore represent an improvement in the quality of the datasets over time. However, it also means that comparing the weighted averages across the surveys is must be done with care. Trends may be obscured by changes in participation in the surveys. The weighted average results presented in this edition of the report should therefore not be compared directly with the weighted average results in the previous editions of the report without fully appreciating the changes in participation. 
Furthermore, lightweighting efforts mean that corrugated base paper base weights (measured in grams per square metre) have been reduced over time. Between the 2021 survey and the 2023 survey there has been a 2% reduction, and over the past ten years the reduction has been approximately 5%.
The effect of these lightweighting efforts mean that energy consumption per tonne of production will not decrease at the same rate as energy consumption per square metre of production (and in some survey years energy consumption per tonne may even show an increase compared to the previous survey, despite more energy efficient production per square metre.
Furthermore, there is a continued drive to improve recycled fibre quality and an increase in sizing and coated papers, which may have also have contributed additional energy demands per tonne of production. As the papermill is considered as a black box, it is not possible to ascertain how much this trend has influenced the results of the life cycle inventory, but this qualitative information provides some context to some of the results achieved and trends observed over time.