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[XT] xtunitroot -- Panel-data unit-root tests
Syntax
Levin-Lin-Chu test
xtunitroot llc varname [if] [in] [, LLC_options]
Harris-Tzavalis test
xtunitroot ht varname [if] [in] [, HT_options]
Breitung test
xtunitroot breitung varname [if] [in] [, Breitung_options]
Im-Pesaran-Shin test
xtunitroot ips varname [if] [in] [, IPS_options]
Fisher-type tests (combining p-values)
xtunitroot fisher varname [if] [in], {dfuller | pperron} lags(#) [Fisher_options]
Hadri Lagrange multiplier stationarity test
xtunitroot hadri varname [if] [in] [, Hadri_options]
LLC_options Description
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trend include a time trend
noconstant suppress panel-specific means
demean subtract cross-sectional means
lags(lag_spec) specify lag structure for augmented Dickey-Fuller (ADF) regressions
kernel(kernel_spec) specify method to estimate long-run variance
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lag_spec is either a nonnegative integer or one of aic, bic, or hqic followed by a positive
integer.
kernel_spec takes the form kernel maxlags, where kernel is one of bartlett, parzen, or
quadraticspectral and maxlags is either a positive number or one of nwest or llc.
HT_options Description
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trend include a time trend
noconstant suppress panel-specific means
demean subtract cross-sectional means
altt make small-sample adjustment to T
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Breitung_options Description
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trend include a time trend
noconstant suppress panel-specific means
demean subtract cross-sectional means
robust allow for cross-sectional dependence
lags(#) specify lag structure for prewhitening
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IPS_options Description
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trend include a time trend
demean subtract cross-sectional means
lags(lag_spec) specify lag structure for ADF regressions
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lag_spec is either a nonnegative integer or one of aic, bic, or hqic followed by a positive
integer.
Fisher_options Description
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* dfuller use ADF unit-root tests
* pperron use Phillips-Perron unit-root tests
* lags(#) specify lag structure for prewhitening
demean subtract cross-sectional means
dfuller_opts any options allowed by the dfuller command
pperron_opts any options allowed by the pperron command
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* Either dfuller or pperron is required.
* lags(#) is required.
Hadri_options Description
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trend include a time trend
demean subtract cross-sectional means
robust allow for cross-sectional dependence
kernel(kernel_spec) specify method to estimate long-run variance
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kernel_spec takes the form kernel [#], where kernel is one of bartlett, parzen, or
quadraticspectral and # is a positive number.
varname may contain time-series operators; see tsvarlist.
Menu
Statistics > Longitudinal/panel data > Unit-root tests
Description
xtunitroot performs a variety of tests for unit roots (or stationarity) in panel datasets.
The Levin-Lin-Chu (2002), Harris-Tzavalis (1999), Breitung (2000; Breitung and Das 2005),
Im-Pesaran-Shin (2003), and Fisher-type (Choi 2001) tests have as the null hypothesis that all
the panels contain a unit root. The Hadri (2000) Lagrange multiplier (LM) test has as the
null hypothesis that all the panels are (trend) stationary. The top of the output for each
test makes explicit the null and alternative hypotheses. Options allow you to include
panel-specific means (fixed effects) and time trends in the model of the data-generating
process.
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