How are the source data aggregated to construct the six WGI measures?
Individual questions from the underlying data sources are assigned to each of the six aggregate indicators. For example, a firm survey question on the regulatory environment would be assigned to Regulatory Quality, or a measure of press freedom would be assigned to Voice and Accountability. A full description of the individual variables used in the WGI and how they are assigned to the six aggregate indicators is available at www.govindicators.org. Multiple questions from the same source are also averaged together. Each one of the six aggregate WGI measures are then constructed as a weighted average of the rescaled data from the individual sources, using a statistical technique known as an unobserved components model (UCM). The rescaling of the variables reflects the fact different indicators use different explicit and implicit units to measure governance. he weights in each year reflect the pattern of correlation among sources in that year: the UCM assigns more weight to sources that a
