What accounts for changes over time in country scores on the WGI?
Changes in governance over short year-to-year periods are difficult to measure with any kind of data, and are typically quite small. Recognizing this, users of the WGI should in most cases not focus on short-run year-to-year changes but rather in trends over longer periods. As with comparisons across countries, comparisons of governance scores for one country over time need to take into account margins of error: if confidence intervals for governance estimates in two periods overlap, the WGI data should not be interpreted as signaling meaningful changes in governance. The vast majority of year-to-year changes in the WGI are too small relative to margins of error to be viewed as statistically, or practically, significant, and so should not be over-interpreted as indicating a significant change in governance performance. However, over longer periods of time such as a decade, the WGI data do show significant trends in governance in a number of countries. Changes over time in a country’s s
