Student test-taking effort in low-stakes assessments: evidence from the English version of the PISA 2015 science test

Large-scale Assessments in Education

An IERI – International Educational Research Institute Journal

Table 8 Percentage of variance in science achievement explained by student test-taking effort

Country	Cluster	% of gross variance explained	% of net variance explained	% of joint variance explained (with all predictors)	% of joint variance explained (with expectancy-value, attitude towards school and science var.)	Proportion of the net % of var. in the gross % of var. explained
AUS	1	14.06	5.63	8.42	7.64	0.40
	2	25.36	9.89	15.47	13.72	0.39
	3	25.61	11.04	14.57	13.08	0.43
	4	32.66	14.40	18.26	16.02	0.44
CAN	1	10.92	6.00	4.92	3.75	0.55
	2	14.39	7.44	6.95	5.56	0.52
	3	17.14	9.02	8.11	7.34	0.53
	4	22.63	11.76	10.87	9.32	0.52
GBR	1	13.01	7.85	5.17	5.41	0.60
	2	23.01	13.19	9.82	8.77	0.57
	3	21.51	11.62	9.89	9.50	0.54
	4	26.71	13.31	13.40	12.54	0.50
IRL	1	11.38	4.73	6.65	5.94	0.42
	2	15.84	6.34	9.50	8.40	0.40
	3	17.05	7.58	9.47	8.37	0.44
	4	22.31	10.94	11.37	10.00	0.49
NZL	1	11.71	5.54	6.17	6.28	0.47
	2	21.13	8.66	12.47	11.79	0.41
	3	22.04	8.13	13.91	12.07	0.37
	4	29.32	10.91	18.41	16.70	0.37
USA	1	9.68	6.15	3.54	3.44	0.63
	2	20.12	10.67	9.45	7.55	0.53
	3	18.98	9.63	9.35	8.79	0.51
	4	26.46	12.05	14.40	11.66	0.46

Small discrepancies with the squared correlations of Table 7 are due to the listwise deletion of students with missing values on the covariates used for the analysis of Table 8.