CalDEC built the California Doughnut over two years of research, in collaboration with academic, government, and community partners across the state. The team considered more than 200 candidate indicators and selected 42 representative ones across 21 categories: 24 social indicators measuring whether Californians have what they need, and 18 ecological indicators measuring whether our economic activity is staying within Earth's limits.
Around half of the indicators draw from government sources, with the rest from NGO reports and peer-reviewed academic work.