PISA was implemented in each country by a National Project Manager (NPM) who implemented the procedures prepared by the consortium. Each NPM typically had several assistants, working from a base location that is referred to throughout this report as a national centre (NC). For the school level operations the NPM coordinated activities with school level staff, referred to as school co-ordinators (SCs). Trained test administrators (TAs) administered the PISA assessment in schools.