National IQ datasets vary due to methodological differences. Averaging multiple sources maximizes accuracy. Chinese IQ estimates range from 89 to 107 across sources. White British IQ normalized to mean 100 SD 15. World IQ is 85.6 weighted by population. Composite estimates predict external outcomes best. Use SPI indicators to validate IQ sets. Low world average driven by populous low-IQ nations. Methodological biases cancel out in averages. Preprint provides detailed national IQ map.