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A Systems View Across Time and Space

Table 2 Panel unit root test results for R&D share, number of patents and PCGDP growth rate

From: Interplays among R&D spending, patent and income growth: new empirical evidence from the panel of countries and groups

Method

Null hypothesis

Test statistics with intercept (prob.)

Test statistics with intercept & trend (prob.)

  

R&D

Patent

PCGDPGrth

R&D

Patent

PCGDPGrth

Levin, Lin and Chu

Unit root (under common unit root process)

− 4.845 (0.00)

− 4.235 (0.00)

− 14.94 (0.00)

− 4.433 (0.00)

− 4.40 (0.00)

− 13.82 (0.00)

Bruitang t test

Unit root (under common unit root process)

-

-

-

− 4.35 (0.00)

− 4.58 (0.00)

− 10.92 (0.00)

Im, Pesaran and Shin

Unit root (under individual unit root process)

− 4.81 (0.00)

− 4.279 (0.00)

− 13.50 (0.00)

− 3.811 (0.00)

− 3.90 (0.00)

− 12.35 (0.00)

MW-ADF–Fisher chi-square

Unit root (under individual unit root process)

74.39 (0.00)

70.256 (0.00)

198.92 (0.00)

60.245 (0.00)

62.31 (0.00)

164.24 (0.00)

MW-PP– Fisher chi-square

Unit root (under individual unit root process)

150.02 (0.00)

105.80 (0.00)

1051.12 (0.00)

158.86 (0.00)

95.97 (0.00)

965.24 (0.00)

  1. Note: Automatic lag length selection is based on AIC: 1 to 4. Probabilities for Fisher tests (source: computed by the authors using Eviews)