The HPFEVENTS Procedure

specifies a valid SAS variable name.

specifies one or more timing values. Each value can be a SAS date keyword, an integer, a SAS date, a SAS datetime, or a do-list. For more information, see the section Event Definitions.

specifies options that control the event definition after the timing value. You can specify the following suboptions within the parentheses:

specifies options that control the event definition before the timing value. You can specify the following suboptions within the parentheses:

specifies a label for the dummy variable for this event definition, where SAS-label is a quoted text string of up to 256 characters. The label is also stored as a description in the data set that is specified in the OUT= option in the EVENTDATA statement. If you do not specify this option, then "." is displayed in the data set that is specified in the OUT=option in the EVENTDATA statement, but the default label ('Dummy Variable for Event variable-name,' where variable-name is the name specified in the EVENT statement) is still used for the dummy variable.

specifies a locale that is associated with the event. The locale should be a POSIX locale value. By default, no locale is associated with the event.

specifies the interval for the frequency of the event. For example, PERIOD=YEAR should produce a dummy value that is periodic in a yearly pattern. If you do not specify this option, the event is not periodic. The PERIOD= option also does not apply to observation numbers (which are not periodic) or to date keywords (which have their own periodicity). For information about which intervals you can specify, see Chapter 4, Date Intervals, Formats, and Functions (SAS/ETS User's Guide).

specifies the interval to be used, which along with the DURATION= suboption in either the AFTER= option or in the BEFORE= option determines the width of the event. The default pulse is one observation. If you specify this option but you do not specify any DURATION= values, the DURATION= values are set to 0. For information about which intervals you can specify, see Chapter 4, Date Intervals, Formats, and Functions (SAS/ETS User's Guide).

specifies the action to take when the defined event has multiple timing values that overlap. When the timing values do not overlap, this option has no impact because only the one defined value for an observation is always used. You can specify the following values:

By default, RULE=ADD.

Because the range of the event that is associated with a timing value might not include all the observations in the series, this option can be interpreted differently when you use multiple timing values in one EVENTDEF statement than when you define a combination event by using the EVENTCOMB statement. Thus, the dummy variables TWOTIMING and TWOEVENTS that are defined in the following statements are different:

   eventdef xmasrp= christmas / before=(slope=growth duration=3)
                                type=ramp rule=min ;
   eventdef easterrp= easter  / before=(slope=growth duration=3)
                                type=ramp rule=min ;
   eventdef twotiming= easter christmas /
                                before=(slope=growth duration=3)
                                type=ramp rule=min ;
   eventcomb twoevents= easterrp xmasrp / rule=min ;

Example 7.1 shows how PROC HPFEVENTS interprets each of these statements.

specifies the number of pulses () by which to shift the timing value. When you specify this option, all timing values in the list (including those generated by date keywords) are shifted. Thus, you can use this option with EASTER to specify ecclesiastical holidays that are based on Easter. Definitions for some moveable Christian holidays based on Easter are given in Reingold and Dershowitz (2001, p. 122). For example, the following statement specifies Good Friday, which is defined as two days before Easter:

EVENTDEF GoodFriday= EASTER / SHIFT=-2 PULSE=DAY;

By default, SHIFT=0, which does not shift the timing value.

specifies a number, , that represents the rate of growth or decay. This number is used as in the growth/decay equation for TYPE=TC, as shown in Table 7. A larger number causes faster growth or decay. This option is ignored unless TYPE=TC. By default, TCPARM=0.5.

specifies the type of the event variable. Each type uses a different formula to create the dummy variables. The formula for each TYPE= option is dependent on other qualifier-options that are specified in this statement. The formula is applied to each timing value that is specified in the timing-value list. You can specify the following values for type: POINT | LS | RAMP | TR | TEMPRAMP | TC | LIN | LINEAR | QUAD | CUBIC | INV | INVERSE | LOG | LOGARITHMIC. Table 8 and Table 9 illustrate the basic shape for each TYPE= value. By default, TYPE=POINT.

specifies the event indicator value. Table 7 provides details about the effect of on the dummy variables. However, for event definitions that have TYPE=POINT | LS | RAMP | TR | TC events and consist of a single timing value that has finite duration, you can think of the event indicator value as the maximum amplitude: the values of the dummy variable should be bounded below by 0 and above by . For trend events (TYPE = LINEAR | QUAD | CUBIC | INV | LOG ), is the coefficient of the term.

By default, VALUE=1.