Corruption Perceptions Index 2012 Short methodology note
Following a rigorous review process, some important changes have been made to the methodology in 2012. The method we use to aggregate different data sources has been simplified and also now includes just one year’s data from each data source. Crucially, this method will allow us to compare scores over time, which was not methodologically possible previously. Given the changes to the methodology, it must be emphasised that country scores of the CPI 2012 cannot be compared against those of 2011 or previous editions. Year to year comparison will be possible from 2012 onwards.
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