Standardization can make autocracies the most extreme outliers by construction.

Evidence

With the Polity data, one consequence of standardization is that the most extreme cases are always autocratic regimes. Because the sample mean is about + 3, the autocratic cases of − 10 always have larger absolute standardized values than do the complete democracy cases with a value of + 10. From a semantic perspective, however, standardization is counterproductive and problematic: the extreme values are “obviously” the − 10 and the + 10 cases. — Gary Goertz, Social Science Concepts and Measurement, 868

Categorization

• SHARE: Send to anyone who works with comparative democracy indices — the asymmetry is a neat ‘gotcha’ with a specific number attached.
• CANDY: Tweetable: on the Polity scale, the biggest outlier is always a dictatorship, purely because the average country is mildly democratic.