Since 2000, INED hosts the headquarters of the International Union for the Scientific Study of Population (IUSSP), the largest demographic institution in the world. In 2005, INED has greatly contributed to the organization of the Union's XXVth world congress that took place in Tours. Many INED researchers are active members of several demographic associations among which is the European Association for Population Study (EAPS), the International Association of French-speaking demographers (EAPS), and the Population Association of America (PAA).