Sustainability Measures: Weighting and Aggregation of Indicators

Transcription

1 Sustainability Measures: Weighting and Aggregation of Indicators Why Weighting and Aggregation? Weighting/Aggregation Difficult/subjective/controversial but inevitable/useful? Morse, S., N. McNamara, M. Acholo, and B. Okwoli Sustainability indicators: The problem of integration. Sustainable Development 9:1-15. A remaining problem is how these diverse SIs are to be integrated into an answer as to whether something is sustainable or not. The values of the aggregated index change with the choice of its component indicators and how they are measured and weighted in the calculation. Choice and weighting are inherently very subjective processes; much depends upon a value judgment as to what is important. 1

2 Some Weighting/Aggregation Methods 1. Equal weighting Justifications for equal weighting - Lack of better choices; convenience; easy to understand [Morse, S., I. Vogiatzakis, and G. Griffiths Space and sustainability: Potential for landscape as a spatial unit for assessing sustainability. Sustainable Development 19:30-48]: Equal weighting is often employed in aggregated indices (e.g. the Human Development Index, HDI, of the UNDP, Morse, 2003, and the Environmental Sustainability Index, ESI) and usually follows more from a lack of evidence that suggests that the weighting should not be equal rather than anything else. The creators of the ESI defended their decision to use equal weighting for their set of 21 indicators as follows: We settled on uniform weighting of the 21 indicators because simple aggregation is transparent and easy to understand. Moreover, when we asked leading experts from the governmental, business, and nongovernmental sectors to rank the indicators, none stood out as being of substantially higher or lower importance than the others Esty et al. (2005), p. 13 While this might sound rather spurious, as the need for clarity is always a convenient defense for ignoring complexity, the justification for equal weighting for the CQI components could be argued to be much the same as given here. 2

3 2. Weighting based on statistical methods Principal component analysis (PCA) Factor analysis Data envelopment analysis (DEA) Regression analysis Etc. 3. Weighting based on expert/public opinion polls Weights assigned directly based on polling results Analytic Hierarchy Process (AHP) Conjoint analysis Etc. Some Examples 3

4 Saisana+Tarantola State- of- the- art Report on Current Methodologies and Practices for Composite Indicator Development.pdf 4

5 Krajnc, D. and P. Glavi A model for integrated assessment of sustainable development. Resources, Conservation & Recycling 43:

6 Recommended references on weighting and aggregation of indicators Jollands, N How to aggregate sustainable development indicators: a proposed framework and its application. International Journal of Agricultural Resources, Governance and Ecology 5: Krajnc, D. and P. Glavi A model for integrated assessment of sustainable development. Resources, Conservation & Recycling 43: Nardo M., Saisana M., Saltelli A. and Tarantola S., Tools for Composite Indicators Building. European Commission, EUR EN, Institute for the Protection and Security of the Citizen, Ispra, Italy. (Available online at ator_building.pdf). OECD, European Commission Joint Research Center: Handbook on Constructing Composite Indicators: Methodology and User Guide. (Available on the internet at Pillarisetti, J. R. and J. van den Bergh Sustainable Nations: What Do Aggregate Indicators Tell Us? Tinbergen Institute Discussion Papers TI /3, Tinbergen Institute. Sands, G. R. and T. H. Podmore A generalized environmental sustainability index for agricultural systems. Agriculture, Ecosystems and Environment 79: Tran, L. T., R. V. O'Neill, E. R. Smith, P. F. Wagner, and M. Mehaffey Watershed- based self- and peer- appraisal indices for integrated environmental assessment with a case study of the Mid- Atlantic region. Ecological Indicators 8: