Table 6.

Comparison of characteristics at baseline, by province.

Variables	Gansu	Shaanxi	Difference
	(1)	(2)	(3) = (2) − (1)
Student:
Grade (1 = fourth)	4.622	4.591	−0.031
	(0.485)	(0.492)	(0.025)
Male sex (1 = yes)	0.517	0.484	−0.032
	(0.500)	(0.500)	(0.024)
Severity of myopia (Logmar-better eye)	0.495	0.522	0.056
	(0.249)	(0.220)	(0.015)
Not wearing eyeglasses at baseline (1 = yes)	0.873	0.832	−0.055 *
	(0.333)	(0.374)	(0.019)
Baseline standardized math score	0.143	0.327	0.090 **
	(0.971)	(0.990)	(0.070)
Math score below the average (1 = yes)	0.501	0.451	−0.049 **
	(0.500)	(0.498)	(0.023)
Family:
One or both parents with high school education or higher (1 = yes)	0.235	0.201	−0.040
	(0.423)	(0.399)	(0.023)
One or both parents out-migrated for work (1 = yes)	0.524	0.428	−0.092 **
	(0.500)	(0.495)	(0.032)
Family asset value, 10 thousand	1.487	4.002	0.353 ***
	(1.899)	(3.757)	(0.238)
Household assets below the average (1 = yes)	0.927	0.606	−0.345 ***
	(0.261)	(0.489)	(0.019)
Teacher & School:
Teachers with college or higher education (1 = yes)	0.487	0.518	0.030
	(0.500)	(0.500)	(0.070)
Share of teachers that held professional titles	0.912	0.883	−0.055
	(0.346)	(0.171)	(0.043)
Class size	47.189	43.365	−0.153
	(10.745)	(12.546)	(1.977)
Half and above material taught on blackboard (1 = yes)	0.831	0.565	−0.271 ***
	(0.375)	(0.496)	(0.062)
Number of observations	762	1325	-

Notes: Columns 1 to 2 present means with standard deviations reported in brackets. Column 3 shows standardized coefficients estimated by regressing each variable on the province dummy, with standard errors, in parentheses, clustered at the school level. * p < 0.10, ** p < 0.05, *** p < 0.01.