Shocks

Use the controls on this page to build a list of shocks which is displayed in the panel at the bottom.

First use the combo box at top left to choose which variable to shock.

If you choose a matrix or vector variable a second row of combo boxes will appear, allowing you to choose whether to shock all of the elements, or only a subset.

Next, choose the value of the shocks. For most variables, a shock of -50 always mean a 50% decrease in the value of that variable. In that case the Type of Shock combo box at the right of the page shows only one option: % change variable. For some tax variables the options % change rate or % change power or % target rate may appear: these are explained in Shocks to tax rates.

For some variables pre-calculated shocks may be available (they will be stored on a file suffixed pre). The Type of Shock combo box will present this file option if it is available. If you choose to use pre-calculated shocks, the Shock Value edit box will disappear (it is irrelevant).

As you select the variable, its elements and the shock value, a shock specification line is built up (above the 4 buttons). The syntax of this line is that used by GEMPACK.

When you have constructed the shock you want, click the Add to Shock List button. Then go on to construct the next shock.

To remove some or all of the shocks you have added to the list, select and delete them.

The Shocks page only allows you to shock variables that have exogenous elements in the current closure. However, it does allow you to specify shocks to endogenous elements of variables that are only partly exogenous. Also, selecting a new closure does not automatically clear the shocks listed on the Shocks page, so that conceivably you could attempt to shock a variable which WAS exogenous in a previous closure, but was now endogenous. In that case, an error will be generated when you attempt to solve the model.

You can also edit the list of shocks directly if you know the GEMPACK syntax for doing this.

For example, you might add statements of the form:

subtotal varname = 1;

assuming varname was a shocked variable. see subtotals.

The menu command Tools...Load Shocks allows you to read in pre-existing files (suffixed SHF) which contain one or more lines of shock statements. See Loading Files of Shocks. The Tools...Save Shocks File command allows you to create such files yourself.

ATTENTION: When using the Shocks page to create new shocks, dont forget to remove any unwanted existing shocks that are already on the list. Use the Clear All Shocks button, or edit the shocks list directly to remove single lines.