Data series have common unit roots in levels but are stationary in first differences: Augmented Dickey-Fuller test results for data series examined in Table 2

Variable Intercept plus trend
Levels Differences
Output to private capital stock ratio −2.282 −7.814***
(0.3397) (0.00)
Private capital stock −0.652 −3.984***
(0.9761) (-0.01)
Labor force −2.521 −6.542***
(0.3177) (0.00)
Public capital stock −1.434 −3.367**
(0.8506) (0.05)

Notes: T-statistics are reported, with p-values in parentheses. Three asterisks denote significance at the 1 percent level, and two asterisks denote significance at the 5 percent level.

Source: Author’s analysis of the data series described in the technical appendix

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