The structural score aggregates 15 structural indicators drawn from Todd, Turchin, Case & Deaton and Putnam. Three are shared with the Canadian and Russian editions — the Turchin index, male life expectancy and the female-male life-expectancy gap — and are computed from the same source, the same series and the same thresholds for all three countries, so the three scores can actually be compared. Elite overproduction and the top 1% income share are no longer scored on their own: they are inputs to the Turchin index, and counting them twice would have double-weighted the same thing.

Thresholds are not chosen. Where a variable is monotonic — longer life is always better, lower infant mortality is always better — the healthy and critical marks are the 10th and 90th percentiles of the observed distribution, world or high-income depending on which one still tells these countries apart without pinning any of them to 100. Fertility is the exception: its world 90th percentile sits near five children per woman, so it is anchored at generational replacement (2.1) instead.

Each indicator also carries its direction of travel, judged against the series' own year-to-year wobble rather than a threshold someone picked. Automated from FRED, CDC WONDER, Census and the World Bank; four indicators are updated manually once a year from their primary source — secularization (Pew), social trust (Gallup), single-parent births (CDC NVSS) and the figures behind the Turchin index. No invented numbers.