Table 3 Results of panel unit root tests...

Table 3

Results of panel unit root tests

Variables	LLC		ADF		CIPS		Inferences
Variables	Level	First dif	Level	First dif	Level	First dif	Inferences
High-income
GDP	4.47	−8.02^***	12.32	116.73^***	1.45	2.54^***	I [1]
Capital	0.65	−11.71^***	11.44	162.02^***	1.85	2.69^***	I [1]
Labour	2.93	−5.56^***	8.67	37.09^***	1.82	3.24^***	I [1]
ICTMob	8.53	−8.56^***	3.33	116.86^***	1.51	2.43^***	I [1]
ICTNet	3.90	−9.83^***	1.80	123.44^***	1.58	3.74^***	I [1]
ICTTel	2.13	−6.95^***	27.43	91.84^***	1.73	2.21^***	I [1]
FD	0.12	−13.19^***	12.99	174.83^***	1.31	3.04^***	I [1]
Trade	1.11	−12.15^***	8.32	163.53^***	1.20	2.73^***	I [1]
FDI	0.13	−4.25^***	10.38	22.25^***	1.70	3.20^***	I [1]
Middle-income
GDP	1.00	−7.27^***	31.32	74.30^***	1.44	2.12^***	I [1]
Capital	4.76	−11.39^***	8.62	157.74^***	1.12	2.56^***	I [1]
Labour	5.21	−3.59^***	2.57	45.94^***	1.64	2.68^***	I [1]
ICTMob	1.74	−9.49^***	15.32	113.93^***	1.19	3.50^***	I [1]
ICTNet	4.83	−8.06^***	12.09	99.73^***	1.44	3.78^***	I [1]
ICTTel	2.39	−4.96^***	23.43	59.87^***	1.62	2.38^***	I [1]
FD	4.42	−8.79^***	4.69	127.22^***	1.71	2.26^***	I [1]
Trade	1.13	−3.22^***	20.03	44.02^***	1.33	2.61^***	I [1]
FDI	1.20	−4.68^***	32.94	77.39^***	1.56	4.44^***	I [1]

Variables	LLC		ADF		CIPS		Inferences
Variables	Level	First dif	Level	First dif	Level	First dif	Inferences
High-income
GDP	4.47	−8.02^***	12.32	116.73^***	1.45	2.54^***	I [1]
Capital	0.65	−11.71^***	11.44	162.02^***	1.85	2.69^***	I [1]
Labour	2.93	−5.56^***	8.67	37.09^***	1.82	3.24^***	I [1]
ICTMob	8.53	−8.56^***	3.33	116.86^***	1.51	2.43^***	I [1]
ICTNet	3.90	−9.83^***	1.80	123.44^***	1.58	3.74^***	I [1]
ICTTel	2.13	−6.95^***	27.43	91.84^***	1.73	2.21^***	I [1]
FD	0.12	−13.19^***	12.99	174.83^***	1.31	3.04^***	I [1]
Trade	1.11	−12.15^***	8.32	163.53^***	1.20	2.73^***	I [1]
FDI	0.13	−4.25^***	10.38	22.25^***	1.70	3.20^***	I [1]
Middle-income
GDP	1.00	−7.27^***	31.32	74.30^***	1.44	2.12^***	I [1]
Capital	4.76	−11.39^***	8.62	157.74^***	1.12	2.56^***	I [1]
Labour	5.21	−3.59^***	2.57	45.94^***	1.64	2.68^***	I [1]
ICTMob	1.74	−9.49^***	15.32	113.93^***	1.19	3.50^***	I [1]
ICTNet	4.83	−8.06^***	12.09	99.73^***	1.44	3.78^***	I [1]
ICTTel	2.39	−4.96^***	23.43	59.87^***	1.62	2.38^***	I [1]
FD	4.42	−8.79^***	4.69	127.22^***	1.71	2.26^***	I [1]
Trade	1.13	−3.22^***	20.03	44.02^***	1.33	2.61^***	I [1]
FDI	1.20	−4.68^***	32.94	77.39^***	1.56	4.44^***	I [1]

Note(s): ***p < 0.01