In the first cycle of PIAAC, three rounds of data collection were carried out, each with a different group of countries. Twenty-four countries participated in the first round (2011/12), nine additional countries joined the second round (2014/15). A third round included five countries (the United States carried out an additional data collection). Data from the first round was published in 2013, the data from the second round was published in 2016. The data from the third round was released in 2019.
