In turn, aggregate measures such as ratios of major tax categories to GDP will reveal much less than detailed and careful analysis of key parameters of different taxes that affect their efficiency and fairness. Many of the countries whose tax systems were assessed in OECD Economic Surveys during the past decade made progress in the pursuit of greater efficiency and fairness, even if aggregate measures do not reflect fully those reforms. Among the countries reviewed over the past decade, two examples of this incrementalism—the Czech Republic and Sweden—are illustrative.