Table 7.

ADF, ADF-GLS and KPSS Unit root tests for stationarity analysis of first differenced series (α = 0.05)

SeriesDiff Log IBOVESPA_1Diff Log CHISHA_1Diff Log DAX 30_1Diff Log IND_BOMB_1DiffLog FTSE 100_1DiffLog NYSE_1DiffLog AL Index_1
ADF with const−42.69−43.58−44.47−40.85−42.01−43.82−36.04
p-value0.00*0.00*0.00*0.00*0.00*0.00*0.00*
ADF with const and trend−43.23−43.58−44.49−40.84−42.01−43.83−36.04
p-value0.00*0.00*0.00*0.00*0.00*0.00*0.00*
ADF_GLS τ−2.12−9.09*−3.85*−4.18*−42.00*−31.04*−28.23*
Critical value−2.89−2.89−2.89−2.89−2.89−2.89−2.89
KPSS3.130.07*0.18*0.11*0.06*0.17*0.12*
Critical value0.4620.4620.4620.4620.4620.4620.462
Testing down from 25 lags and BIC criterion for ADF and ADF-GLS; Lag order 8 for KPSS
SeriesDiffLog IBOVESPA_2DiffLog CHISHA_2DiffLog DAX 30_2DiffLog IND_BOMB_2DiffLog FTSE 100_2DiffLog NYSE_2DiffLog AL Index_2
ADF with const−76.82−73.07−75.21−69.61−29.00−80.77−80.92
p-value0.00*0.00*0.00*0.00*0.00*0.00*0.00*
ADF with const and trend−76.82−73.06−75.21−69.61−29.00−80.77−80.93
p-value0.00*0.00*0.00*0.00*0.00*0.00*0.00*
ADF_GLS τ−2.36−2.77−17.39*−4.26*−29.63*−2.97*−10.73*
Critical value−2.89−2.89−2.89−2.89−2.89−2.89−2.89
KPSS0.07*0.06*0.15*0.09*0.09*0.07*0.14*
Critical value0.4620.4620.4620.4620.4620.4620.462
Testing down from 32 lags and BIC criterion for ADF and ADF-GLS; Lag order 10 for KPSS

Notes:

Table resumes the formal unit-root tests for first differenced log-series. Augmented Dickey-Fuller (ADF), Augmented Dickey-Fuller Generalized Least Squares Regression (ADF-GLS) and Kwiatkowsky-Phillips-Schmidt-Shin (KPSS) test are calculated with the corresponding p-value. Lag adjustments are because of different sample sizes.

*

Indicates stationarity at 5% level (α = 0.05)

Source: Personal elaboration on Datastream (2021) 

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