@after |

Indicator series for whether an observation postdates a given date.

Syntax: @after(d)

d: string, alpha

Return: series

Returns a series containing indicators for whether each observation postdates the corresponding date d.

• For dates d that are of equal or lower frequency than the observation, the results are (0, 1) indicators of whether the observation is on or after the beginning of d.

• For dates d that are of higher frequency than the observation, the (0, n) results reflect the fraction of the observation on or after the beginning of d.

Examples

Suppose that we have a quarterly workfile with data from 2020q1 to 2022q4 that we create with the command:

workfile q 2020 2022

The command

series after_y = @after("2021")

uses a lower-frequency “yearly” date to creates the series AFTER_Y containing the value 1 from 2021q1 through the end of the workfile, and 0 elsewhere.

Using a “quarterly” date,

series after_q = @after("2021q3")

creates the series AFTER_Q containing the value 1 beginning in 2021q3 through the end of the workfile, and 0 elsewhere.

The command using a higher frequency “monthly” date

series after_m = @after("2021m5")

generates the series AFTER_M containing the value 0 from 2020q1 through 2021q1, a fractional value for 2021q2, and the value 1 from 2021q3 through the end of the data.

For the fractional 2021q2 value, there are 61 days in 2021-May and 2021-June that are after the beginning of the “2021m5” date and 91 days in the full quarter, so the fractional value for 2021q2 is 61/91 = 0.67033.

Cross-references