The Impact of Assignments and Quizzes on Exam Grades: A Difference-in-Difference Approach

Figures & data

Table 1 Descriptive statistics.

	Section 1^a	Section 2^b	Section 3^c
Male	15 (50%)	18 (67%)	23 (68%)
Female	15 (50%)	9 (33%)	11 (32%)
Domestic	22 (73%)	6 (22%)	12 (35%)
International	8 (27%)	21 (78%)	22 (65%)
GPA	3.13	2.76	2.97
Midterm 1 average grade	62	56	57
Midterm 2 average grade	60	76	69
Sample size	30	27	34

Source: Primary survey.

a Section 1 is the section with neither assignments nor quizzes.

b Section 2 is the section with assignments but no quizzes.

c Section 3 is the section with quizzes but no assignments.

Table 2 Descriptive statistics: GPA by gender and residency.

	Section 1	Section 2	Section 3
Male	2.97	2.67	2.84
Female	3.27	2.92	3.24
Domestic	3.17	2.90	3.22
International	3.09	2.72	2.84
Sample size	30	27	34

Source: Primary survey.

Table 3 DID estimation with assignments as treatment.

Variables	Coefficient
Time	–1.20
	(0.9)
Treated	–1.93
	(0.8)
Difference-in-difference estimator	23.53
	(0.009)
Male	3.15
	(0.5)
International student	–10.15
	(0.04)
GPA	26.84
	(0.000)
Constant	–14.55
	(0.3)
Number of observations	114

NOTE: p-values are shown in the parentheses.

Table 4 DID estimation with quizzes as treatment.

Variables	Coefficient
Time	–1.20
	(0.9)
Treated	–3.66
	(0.6)
Difference-in-difference estimator	13.31
	(0.2)
Male	6.31
	(0.2)
International student	–0.148
	(0.9)
GPA	24.92
	(0.000)
Constant	–17.47
	(0.2)
Number of observations	128

NOTE: p-values are shown in the parentheses.

Table 5 DID estimation with assignments as treatment, by gender.

	Coefficient	Coefficient
Variables	(male sample)	(female sample)
Time	–0.33	–2.06
	(0.9)	(0.8)
Treated	–5.91	6.83
	(0.6)	(0.6)
Difference-in-difference estimator	24.24	24.29
	(0.05)	(0.2)
International student	–9.74	–5.39
	(0.2)	(0.6)
GPA	28.00	25.37
	(0.000)	(0.000)
Constant	–13.24	–15.72
	(0.5)	(0.4)
Number of observations	66	48

NOTE: p-values are shown in the parentheses.

Table 6 DID estimation with quizzes as treatment, by gender.

	Coefficient	Coefficient
Variables	(male sample)	(female sample)
Time	–0.33	–2.06
	(0.9)	(0.9)
Treated	–9.91	7.42
	(0.3)	(0.6)
Difference–in–difference estimator	19.37	–0.296
	(0.2)	(0.9)
International student	0.75	–0.260
	(0.9)	(0.9)
GPA	21.18	30.96
	(0.000)	(0.000)
Constant	0.78	–38.47
	(0.9)	(0.05)
Number of observations	76	52

NOTE: p-values are in the parentheses.

Table 7 DID estimation with assignments as treatment, by student residency.

	Coefficient	Coefficient
	(domestic student	(international student
Variables	sample)	sample)
Time	8.37	–4.68
	(0.4)	(0.6)
Treated	10.05	–14.94
	(0.3)	(0.3)
Difference-in-difference estimator	15.65	25.41
	(0.3)	(0.09)
Male	1.55	9.03
	(0.9)	(0.3)
GPA	27.21	27.90
	(0.000)	(0.000)
Constant	–24.96	–26.62
	(0.2)	(0.2)
Number of observations	56	58

NOTE: p-values are shown in the parentheses.

Table 8 DID estimation with quizzes as treatment, by student residency.

	Coefficient	Coefficient
	(domestic student	(international student
Variables	sample)	sample)
Time	8.37	–4.68
	(0.4)	(0.6)
Treated	1.93	–7.59
	(0.9)	(0.5)
Difference–in–difference estimator	0.71	22.35
	(0.9)	(0.05)
Male	5.60	6.50
	(0.5)	(0.4)
GPA	25.93	23.87
	(0.000)	(0.000)
Constant	–24.17	–12.82
	(0.3)	(0.4)
Number of observations	68	60

NOTE: p-values are shown in the parentheses.

Table 9 DID estimation with assignments as treatment.

Variables	Coefficient
Time	–2.59
	(0.000)
Treated	–8.54
	(0.3)
Difference–in–difference estimator	15.76
	(0.05)
Male	4.81
	(0.3)
International student	–1.89
	(0.8)
GPA	20.12
	(0.000)
Constant	1.65
	(0.9)
Number of observations	110

NOTE: p-values are shown in the parentheses.

Table 10 DID estimation with quizzes as treatment.

Variables	Coefficient
Time	–2.58
	(0.000)
Treated	–3.85
	(0.6)
Difference–in–difference estimator	31.88
	(0.000)
Male	3.57
	(0.5)
International student	0.318
	(0.5)
GPA	22.17
	(0.000)
Constant	–7.85
	(0.6)
Number of observations	124

NOTE: p-values are shown in the parentheses.