Date Notation

You refer to observations by date in RATS using one of the following formats:

year:period	annual, monthly, quarterly, other periods per year, or years per period. For example, for monthly data, 2013:12 is December, 2013. For annual data, 2003:1 is the year 2003.
year:month:day	weekly, daily, etc. (2014:5:15 for May 15, 2014)
year:month:day//period	intraday data. (2000:12:1//3 for the third observation on December 1, 2000)
individual//date	dated or undated panel data
individual//period	dated or undated panel data

You can also use year:period for weekly or daily data; it will give you the indicated week or day (business day for business day data) within the year. With seven-day data, 2013:35 would be the February 4th observation (35th period for that year).

Also, with annual data, you must use year:1, and not just year, for a date, as RATS won’t recognize it as a date except in that form.

Century and “Year 2000” Issues

RATS allows you to use two digits for year references in a date. However, for backwards compatibility with older RATS code, the program assumes that these refer to 20th century dates (19xx). To avoid confusion and mistakes in reading your data, we strongly recommend you use four-digit year references in all of your programs and data sets.

If you still have existing data sets (such as RATS format files) that have been created using two-digit date formats, define a CALENDAR using a four-digit year, read the data into RATS, and then write the data back out—this will update the file so that it contains four-digit year information.