Where 12 Axes came from
8values set the template: agree-or-disagree statements, each nudging you along one axis, with results shown as split bars and a closest ideology. 9axes added more axes, and 12 Axes reorganised and patched 9axes into twelve axes in four groups. It keeps the 8values ideology list, so the ideology match uses the four axes that line up with 8values: Economy, Power, Diplomacy and Culture.
What the extra axes tell you
Two people can both be "economically right" on 8values and still disagree a lot. One might want private ownership with strict regulation; the other might want no regulation at all. 12 Axes separates those into Economy and Control. In the same way it separates Diplomacy from Trade and Military, and gives religion, immigration, government structure and technology their own axes.
Which should you take?
If you want a quick, familiar label to compare with friends, the Political Compass and 8values are well known. If you want to see the detail behind that label, especially on issues like AI, trade or immigration, take 12 Axes. The quick version is shorter than 8values.