Table 4. Two-way fixed effects panel regressions (clustering, with interaction) of average log nightlight intensity on major special economic zones (January 2020 to January 2022)

Variables	(9)Log nightlight activity	(10)Log nightlight activity	(11)Log nightlight activity
Sinuiju	2.632***(0.08211)
Rason		0.1117(0.06238)
Kaesong			0.7220***(0.06227)
Provincial population density (people/km2)	0.001410***(0.00001144)	0.0007075***(0.00009842)	0.001410***(0.0001144)
Nightlight activity×Provincial pop. density	–0.0001172***(0.00001161)	–0.00004335***(0.00000984)	–0.0001172***(0.00001161)
Constant	–1.983***(0.02494)	–2.015***(0.02832)	–1.989***(0.02789)
Observations	3,534	3,534	3,534
Adjusted R2	0.3303	0.2945	0.3199

Standard errors in parentheses.
p<0.001.