The National Death Index is a cross-national mortality reference. It takes public figures about nations, organizes them by nation, and compares them across nations. That's the whole product: a number, a rank, a source, and a date. We present the data and stop. You draw the conclusion.
Several governments run something called a "National Death Index" in the internal sense — the United States (CDC/NCHS) and Australia (AIHW) both operate restricted, researcher-only databases that link study cohorts to individual death certificates inside their own borders. This site is not one of those, and never will be. We hold no records on individuals, we never identify a person, and we offer no death-record lookup of any kind. "National" here means comparative: data about nations, not records within one.
Mortality has more than one true measure, and they answer different questions. A crude death rate counts deaths per 1,000 residents of any age — a real fact about a society, but one that rises wherever the population is old. Age-standardized rates reweight every country onto one standard age structure, so a young country and an old one can be compared fairly. Adult mortality counts the probability of dying between 15 and 60, independent of age structure entirely.
None of these is the "right" one. They count different things. Our only rule is that every view states, once and plainly, what its measure counts. Hiding a correct number because a reader might misread it would distort as much as inventing one. So we show the number and its definition together, and let you pick the question you're asking. Where a rate is age-confounded — the crude death rate above all — the page says so in the same breath it shows the figure.
The spine is World Bank Open Data: free, no key, around 200 countries, decades deep, and redistributable. Life tables and a handful of age-standardized rates come from the WHO Global Health Observatory (Global Health Estimates 2021). Every figure on every page carries its source and the exact year it was reported. The latest available year differs by country, so two rows in the same table may be stamped with different years; we show each one rather than forcing a single date and hiding the gaps.
The age-standardized death rate reweights each country's age-specific death rates onto the WHO World Standard Population (Ahmad et al., 2001), expressed across the standard abridged age groups. The result strips out the effect of a country's age structure and leaves the mortality signal. It reorders the crude-rate list completely — and that reorder is the point, not a caveat.
A few measures are computed at ingest rather than pulled directly: military spending per capita (total military expenditure divided by population for the same year), the life-expectancy gap (female minus male at birth), the old-age sex ratio (men per 100 women among those 65 and over), and obesity prevalence (the mean of the male and female adult rates, since the World Bank carries the two separately). Each is defined on the data sources page.
A cross-country snapshot hides things. It can't see the difference between a rich person and a poor one inside the same country, and it freezes a moving picture into a single frame. Correlation is not causation, and we say so once, plainly, in the footer of every page rather than hedging every sentence. Where a relationship is largely a proxy for national wealth, we flag it on the page rather than trumpet it. Honesty about the limits is part of the product.