{% extends "base.html" %}
{% block title %}Myrdal — Demography & Migration · myrdal.heterodata.org{% endblock %}
{% block content %}
<section class="ark-wrap ark-hero">
  <h1>Myrdal — Demography &amp; Migration</h1>
  <p class="ark-lede">Population is not a backdrop to the economy. Age structure sets who can work and who must be supported; migration moves labour and demand between places; fertility and mortality decide both, decades in advance. Myrdal assembles {{ meta.counts.series_published }} demographic series — {{ "{:,}".format(meta.counts.observations_total) }} observations — from named public statistical sources, so those forces can be read directly rather than assumed.</p>
</section>

{# Research Triad, server-rendered from this site's own ecosystem `cdf` block
   (adapters/jinja_triad.html.j2). Visible with no JavaScript, above the fold:
   a visitor who wants the data and the code and nothing else is a first-class
   user (CODE_DATA_FIRST_STANDARD.md §B1.1). #}
{% include "_shared/adapters/jinja_triad.html.j2" %}

<section class="ark-wrap ark-grid">
  <a class="ark-card" href="/explore"><h3>Explore →</h3><p>{{ meta.counts.series_chartable }} of the {{ meta.counts.series_published }} series can be charted directly in the browser, across {{ meta.counts.categories }} source families — world population, the demographic transition, United States counties, and internal migration.</p></a>
  <a class="ark-card" href="/data"><h3>Data →</h3><p>Every series as CSV, XLSX and Parquet, with a {{ meta.counts.data_dictionary_rows }}-row data dictionary and a per-series provenance record. One bundle for everything.</p></a>
  <a class="ark-card" href="/methodology"><h3>Methodology →</h3><p>Where each number comes from, how far it really runs, and what is missing — including the two series that are registered but empty.</p></a>
</section>

<section class="ark-wrap ark-prose">
  <h2>What is here</h2>
  <p>Four bodies of evidence, kept separate because they answer different questions.</p>
  <ul>
    <li><strong>The long run.</strong> World and country population from year {{ meta.by_id['D001'].first_observation }} CE to {{ meta.by_id['D001'].last_real_observation }}, stitched from the Maddison Project and Clio-Infra before 1960 and the World Bank's World Development Indicators after it — the seam is recorded in a <code>source</code> column inside the file itself, not hidden in a footnote.</li>
    <li><strong>The transition.</strong> Fertility, crude birth and death rates, life expectancy, under-five mortality and the youth and old-age dependency ratios, by country, on World Development Indicators.</li>
    <li><strong>United States counties.</strong> Population, median age, race and ethnicity, nativity, income, labour force and housing for 3,231 counties on the American Community Survey five-year estimates, plus the Population Estimates Program age bands.</li>
    <li><strong>Who moved.</strong> County-to-county and state net migration from Internal Revenue Service Statistics of Income filings, which key on a filing-year <em>pair</em> — a flow spans two years and is labelled that way here.</li>
  </ul>
  <h2>Three things the data says</h2>
  <ul>
    <li>World population reached <strong>8.14 billion</strong> in 2024 on the World Bank's own world aggregate, and <strong>8.12 billion</strong> when the individual countries are summed — the two differ, and both are in the file (<code>D001</code>).</li>
    <li><strong>13.6 %</strong> of the United States population was foreign-born in 2022, and the state figure ranges from <strong>26.5 %</strong> in California to <strong>1.6 %</strong> in West Virginia (<code>D049</code>, 52 state-level rows including the District of Columbia and Puerto Rico).</li>
    <li>Summed across all counties the total dependency ratio is <strong>0.549</strong> and the old-age ratio <strong>0.275</strong> — about 28 people aged 65 or over for every 100 of working age (<code>D058</code>, Population Estimates Program 2023 vintage).</li>
  </ul>
  <p class="ark-fineprint">An <a href="{{ hub_url }}">Arcanum Research</a> project · Anu Framework v12.2 · every value traces to a published source; no synthetic or estimated data. Named for <a href="/about">Gunnar Myrdal</a>.</p>
</section>
{% endblock %}