Elevated atmospheric CO2 alleviates drought stress in wheat

Much progress has been achieved in defining indicators of impact and change at national and international levels. Concern has been raised about data quality, standardisation methods and aggregation issues. This paper addresses these issues for multidisciplinary studies at a project level, from where data are aggregated to supply national databases. Component indicators of different types are identified and problems of forming composites, weighting and aggregation are discussed. Initial suggestions for robust design and analysis to monitor change in a multidisciplinary way are given. Many system databases are not truly multidisciplinary and until these are available the necessary research to underpin good data quality may not be possible. Guidelines for the handling of indicators of the different types are given. Suggestions are provided for the inclusion of stakeholders at all project stages to identify issues and indicators, to liaise over project results and to encourage ownership of the data.