One of the more distinctive features on Mentometry is the country leaderboard, a ranking that aggregates every player’s performance by the country they’ve selected as their place of residence. It sits alongside a number we call the Brain Index, and because it’s easy to misread a number like that, it’s worth explaining exactly how it’s calculated and, just as importantly, what it deliberately does not claim to measure.
The starting point is normalization. Mentometry’s 28 games are scored on completely different scales — a strong result in Color Clash might be a few hundred points, while a strong result in Obstacle Jump could run into the thousands. Comparing raw scores across games would be meaningless, so every player’s score in a given game is first converted to a percentage of the best verified score anyone has achieved in that specific game. That normalized value, on a common 0-to-1000 scale, is what actually gets summed across the games a player has completed to produce their overall ranking.
The country leaderboard takes that same normalized data and groups it by country. Two numbers are shown for each country: the total combined score of everyone who has played from that country, and the Brain Index, which is the average normalized score of that country’s players, scaled against the global average across all players. A Brain Index of 100 means a country’s average player performance sits exactly at the global average; a higher number means the average player from that country is outperforming the global average, and a lower number means the opposite.
Here’s the part we want to be unambiguous about: the Brain Index is not a measure of national intelligence, and it isn’t intended to resemble the kind of psychometric national IQ comparisons that have generated real controversy in academic and public discourse over the years. Mentometry’s player base for any given country is self-selected, almost certainly skews toward people who enjoy this specific kind of game, and for smaller countries may consist of just a handful of players — which is exactly why countries with fewer than five recorded players are explicitly flagged as “low data” wherever the index is shown. A single enthusiastic player from a small country can swing that country’s number dramatically, which tells you something about sample size, not about a nation’s collective cognitive ability.
What the Brain Index is meant to be is a fun, competitive framing for a leaderboard that would otherwise just be a list of individual names. It gives players another reason to keep playing beyond their own personal best — the sense that every game contributes, even a little, to how their country stacks up against the rest of the world. Treat it the way you’d treat a friendly office pool or a casual sports rivalry: genuinely fun to follow, not something to cite as evidence of anything beyond itself.
If you want to see where your country currently stands, the “By Country” tab on the Mentometry leaderboard updates continuously as new scores come in — and if your country isn’t near the top yet, that’s as much an invitation as anything else.
