Frequently, it is desirable to compute time on a monthly basis but survey model results on a yearly basis. In this case variables can be added to the list above to make the month-to-year conversion, and Vensim can be instructed to report results on a calendar (and/or fiscal) year basis, e.g.,
Decimal year = TIME BASE(INITIAL YEAR,YEARS PER MONTH)
| ~ | year |
| ~ | decimal year date. |
|
INITIAL YEAR = 1980
| ~ | year |
| ~ | Start simulation on January 1, 1980. |
|
YEARS PER MONTH = .083333
| ~ | year/month |
~ The number of years in a month.
|
When using different Time Bases, be careful to specify the basis on which data is entered. If data is on an annual basis and the model is in months an equation such as the one above must be included, and the data must be marked as using the time base Decimal year.
