Object Reference : Object View and Procedure Reference : Series
  
 
bubbletest
Perform tests on the existence of a bubble in the series.
Calculate either the rolling ADF (RADF), supremum ADF (SADF) or generalized supremum ADF (GSADF) test for the existence of a bubble in an asset.
Syntax
series_name.bubbletest(options)
Options
 
test=arg
Specify the type of test to perform. Use “SADF” to perform the supremum ADF test, and “GSADF” to perform the generalized supremum ADF test.
By default, the rolling ADF test is performed.
window=int
Set the length of the rolling window (for RADF test), or the initial window length (for SADF and GSADF tests).
exog=arg
Specification of exogenous trend variables in the test equation: “trend” (include a constant and a linear time trend), “none” (do not include any exogenous regressors). By default, a constant is included.
lagmethod=arg
Method for selecting lag length (number of first difference terms) to be included in the Dickey-Fuller test regression or number of lags in the AR spectral density estimator: “aic” (Akaike), “sic” (Schwarz), or “hqc” (Hannan-Quinn).
lag=int
User-specified fixed lag.
maxlag=int
Maximum lag length to consider when performing automatic lag length selection.
reps=arg
Number of bootstrap replications.
seed=int
Set the random number generator seed.
rng=arg
Set random number generator type. Available types are: improved Knuth generator (“kn”), improved Mersenne Twister (“mt”), Knuth’s (1997) lagged Fibonacci generator used in EViews 4 (“kn4”), L’Ecuyer’s (1999) combined multiple recursive generator (“le”), Matsumoto and Nishimura’s (1998) Mersenne Twister used in EViews 4 (“mt4”).
nocv
Do not display critical value line in graph.
cvsig=arg (default=0.95)
Critical value for display in graph and for critical value output series (using “cvout=”).
out=name
Name of a series to hold the test statistics.
cvout=name
Name of a series to hold the test critical values.
prompt
Force the dialog to appear from within a program.
p
Print results.
Examples
spy.bubbletest(test=gsadf, window=30, lagmethod=hqc, seed=40)
Performs a generalized supremum bubble test on the SPY series, with an initial window length of 30 observations, using the Hannan-Quinn Criterion to determine the appropriate lag length, and using a seed value of 40 for the random number generator used in the bootstrapped p-values.
Cross-references
See “Explosive Bubble Tests”.