Evaluating the risk of nonresponse bias in educational large-scale assessments with school nonresponse questionnaires: a theoretical study

Large-scale Assessments in Education

An IERI – International Educational Research Institute Journal

Table 7 R² (explained variance of achievement score) by country (PIRLS)

Country	Participation rate of schools (before replacement) (%)	Standard model	Country-specific model
Country	Participation rate of schools (before replacement) (%)	R² (adj.)	R² (adj.)
Belgium (French)	77	0.55 (0.06)	0.51 (0.08)
England	75	0.55 (0.07)	0.55 (0.07)
Netherlands	68	0.32 (0.09)	0.47 (0.07)
Northern Ireland	62	0.43 (0.09)	0.57 (0.17)
Norway	57	0.28 (0.06)	0.42 (0.12)