1. Correcting for sample problems in PISA and the improvement in Portuguese students' performance. Issue 4 (1st October 2016) Authors: Freitas, Pedro; Nunes, Luís Catela; Balcão Reis, Ana; Seabra, Carmo; Ferro, Adriana Journal: Assessment in education Issue: Volume 23:Issue 4(2016) Page Start: 456 Record Type: Journal Article View Content: Available online (eLD content is only available in our Reading Rooms) ↗