Object Reference : Object View and Procedure Reference : Var
  
 
impulse
Display impulse response functions of var object with an estimated VAR or VEC.
Syntax
var_name.impulse(n, options) ser1 [ser2 ser3 ...] [@ shock_series [@ ordering_series]]
You must specify the number of periods for which you wish to compute the impulse responses.
List the series names in the var whose responses you would like to compute. You may optionally specify the sources of shocks. To specify the shocks, list the series after an “@”. By default, EViews computes the responses to all possible sources of shocks using the ordering in the Var.
If you are using impulses from the Cholesky factor, you may change the Cholesky ordering by listing the order of the series after a second “@”.
Options
 
g (default)
Display combined graphs, with impulse responses of one variable to all shocks shown in one graph. If you choose this option, standard error bands will not be displayed.
m
Display multiple graphs, with impulse response to each shock shown in separate graphs.
t
Tabulate the impulse responses.
a
Accumulate the impulse responses.
imp=arg (default=“chol”)
Type of factorization for the decomposition: unit impulses, ignoring correlations among the residuals (“imp=unit”), non-orthogonal, ignoring correlations among the residuals (“imp=nonort”), Cholesky with d.f. correction (“imp=chol”), Cholesky without d.f. correction (“imp=mlechol”), Generalized (“imp=gen”), structural (“imp=struct”), or user specified (“imp=user”).
The structural factorization is based on the estimated structural VAR. To use this option, you must first estimate the structural decomposition; see Var::svar.
For user-specified impulses, you must specify the name of the vector/matrix containing the impulses using the “fname=” option.
The option “imp=mlechol” is provided for backward compatibility with EViews 3.x and earlier.
fname=name
Specify name of vector/matrix containing the impulses. The vector/matrix must have rows and 1 or columns, where is the number of endogenous variables.
se=arg
Standard error calculations: “se=a” (analytic), “se=mc” (Monte Carlo).
If selecting Monte Carlo, you must specify the number of replications with the “rep=” option.
Note the following:
(1) Analytic standard errors are currently not available for (a) VECs and (b) structural decompositions identified by long-run restrictions. The “se=a” option will be ignored for these cases.
(2) Monte Carlo standard errors are currently not available for (a) VECs and (b) structural decompositions. The “se=mc” option will be ignored for these cases.
rep=integer
Number of Monte Carlo replications to be used in computing the standard errors. Must be used with the “se=mc” option.
matbys=name
Save responses ordered by shocks (impulses) in a named matrix. The first column is the response of the first variable to the first shock, the second column is the response of the second variable to the first shock, and so on. The response and shock orderings correspond to the ordering of variables in the VAR.
matbyr=name
Save responses ordered by response series in a named matrix. The first column is the response of the first variable to the first shock, the second column is the response of the first variable to the second shock, and so on. The response and shock orderings correspond to the ordering of variables in the VAR.
smat=name
Save responses ordered by shocks (impulses) in a named matrix (akin to the “matbys= option). The shocks and responses are ordered according to the user-specified order given by the “@ shock_series and “@ ordering_series specifications.
rmat=name
Save responses ordered by response series in a named matrix (akin to the “matbyr=” option). The shocks and responses are ordered according to the user-specified order given by the “@ shock_series and “@ ordering_series specifications.
prompt
Force the dialog to appear from within a program.
p
Print the results.
Examples
var var1.ls 1 4 m1 gdp cpi
var1.impulse(10,m) gdp @ m1 gdp cpi
The first line declares and estimates a VAR with three variables. The second line displays multiple graphs of the impulse responses of GDP to shocks to the three series in the VAR using the ordering as specified in VAR1.
var1.impulse(10,m) gdp @ m1 @ cpi gdp m1
displays the impulse response of GDP to a one standard deviation shock in M1 using a different ordering.
Cross-references
See “Vector Autoregression and Error Correction Models” for a discussion of variance decompositions in VARs.
See also Var::decomp.