Offsets of <year> in BSH and PSH Files

You can use <year> in BSH and PSH files to indicate the slice to take shocks from.

From Version 3.49 (January 2010), you can select a different slice from the year you are running by using <year+integer or <year-integer in place of <year. Below we give details and examples.

Enhancement for Version 3.56 (September 2010). You can also use "<quarter+/-integer", "<month+/-integer" and "<period+/-integer" for quarterly or monthly models.

Examples

shock <year+1> x4 = file x4.shk header x4 ;

The year+1 adds one to the current year you are running. For example, if you are running the simulation for year 2008, this will take the shock from slice Y2009, while if you are running the simulation for year 2012, this will take the shock from slice Y2013.

shock <year-2=ABC> x4 = file x4.shk header x4 ;

The year-2 subtracts two from the current year you are running. For example, if you are running the simulation for year 2008, this will take the shock from slice ABC2006, while if you are running the simulation for year 2012, this will take the shock from slice ABC2010.

Rules

These are similar to the previous case where no offsets are allowed. The difference is that the integer offset +N or -N affects the date in the slice.

Motivation (via James Giesecke)

In some forecasting simulations, it can be handy to introduce crude forward-looking behaviour. For example, to settle misbehaving investment in certain sectors, it can be useful to anticipate year t+1 capital demands in year t. Doing so allows investment in year t to be adjusted to deliver capital sufficient to meet likely capital demands in year t+1.

As a consequence it may be necessary to shock one variable V1 in year t with the same shocks as another variable V2 is being given in year t+1. Now you can say

shock <year> V2 from file shocks.har header V2 ;

shock <year+1> V1 from file shocks.har header V2 ;

in the BSH or PSH files for the relevant years.

Without the <year+1> possibility, you would need to duplicate the V2 shocks for each year on the shocks file and move them up a year in order to read the V1 shocks -- this is an error-prone and costly procedure. The <year+1> syntax removes the need for such duplication.

URL of this topic: www.copsmodels.com/webhelp/rundynam/hc_offsetyear.htm

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