Date Intervals, Formats, and Functions

Alignment of SAS Dates

SAS date values used to identify time series observations produced by SAS/ETS procedures are normally aligned with the beginning of the time intervals corresponding to the observations. For example, for monthly data for 1994, the date values identifying the observations are 1Jan94, 1Feb94, 1Mar94, ..., 1Dec94.

However, for some applications it may be preferable to use end of period dates, such as 31Jan94, 28Feb94, 31Mar94, ..., 31Dec94. For other applications, such as plotting time series, it may be more convenient to use interval midpoint dates to identify the observations.

SAS/ETS procedures provide an ALIGN= option to control the alignment of dates for output time series observations. Procedures supporting the ALIGN= option are ARIMA, DATASOURCE, EXPAND, and FORECAST.

ALIGN=

The ALIGN= option allows the following values:

BEGINNING: Specifies that dates are aligned to the start of the interval. This is the default. BEGINNING can be abbreviated as BEGIN, BEG, or B.
MIDDLE: Specifies that dates are aligned to the interval midpoint. MIDDLE can be abbreviated as MID or M.
ENDING: Specifies that dates are aligned to the end of the interval. ENDING can be abbreviated as END or E.

The ALIGN= option can be specified on the PROC DATASOURCE statement, on the PROC EXPAND statement, on the PROC FORECAST statement, and on the FORECAST statement of the ARIMA procedure.

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