Example of a Quarterly Model

Suppose that the top of the Sim Overview page shows

•Use Quarters? is checked.

•Start from data representing quarter 2 of year 2003 which we denote by 2003q2. [Start from data for year 2003 and Starting Data Quarter is 2.]

•Number of periods in Base Case is 6.

•Lengths of Periods are 2,3,4,1,1,1 respectively. These are QUARTERS since Use Quarters? is checked for a quarterly model.

Then

•the simulation for the first period produces data for quarter 4 of year 2003 - that is, for 2003q4. Starting data represents 2003q2 and the simulation produces updated data which represents 2003q4 since the simulation covers 2 quarters (length of first period).

•the simulation for the second period produces data for quarter 3 of year 2004 - that is, for 2004q3. This simulation starts from data representing 2003q4 (as produced by the first simulation) and the simulation produces updated data which represents 2004q3 since the simulation covers 3 quarters (length of second period).

•the simulation for the third period produces data for 2005q3 -- starts from data for 2004q3 and simulation covers 4 quarters.

•the simulation for the fourth period produces data for 2005q4 -- starts from data for 2005q3 and simulation covers 1 quarter.

•the simulations for the fifth and sixth periods produce data for 2006q1 and 2006q2 respectively since each simulation covers one quarter.

•the dates shown in the left-hand column on the Closure/Shocks page are 2003q4, 2004q3, 2005q3, 2005q4, 2006q1 and 2006q2 -- these are the dates for which the 6 simulations produce data.

If you change any of the information in these three items, these strings in the left-hand column of the Closure/Shocks page will change.

For example,

•suppose that you indicate to start from data for quarter 1 of year 2006. Then the dates shown on the Closure/Shocks page will be 2006q3, 2007q2, 2008q2, 208q3, 2008q4 and 2009q1.

•suppose that you go back to starting from data for quarter 2 of year 2003 but change the length of the 3rd period to 2 quarters. Then the dates shown on the Closure/Shocks page will be 2003q4, 2004q3, 2005q1, 2005q2, 2005q3 and 2005q4.

•suppose that you revert to the original lengths of the periods but reduce to 4 periods in the Base Case. Then the dates shown on the Closure/Shocks page will be 2003q4, 2004q3, 2005q3 and 2005q4.

Note that the dates shown in the left-hand column of the Closure/Shocks page affect the names of various results files. For example, suppose that the 3-letter names are BAS, BR1 and POL for the Base, Rerun and Policy respectively. Then

•the Solution file for the first period of the Base will be called bas-2003q4.sl4 while the Solution file for the second period of the Policy (assuming that the Policy starts at the same time as the Base) will be called bas-br1-pol-2004q3.sl4.

•the updated version of Starting Data file with logical name IODATA with key IOD (as shown on the Other Files page) after the first period of the Base will be called iod-bas-2003q4.sl4 while the updated version after the second period of the Policy (assuming that the Policy starts at the same time as the Base) will be called iod-bas-br1-pol-2004q3.sl4.

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

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