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Using SELECT IF to recode one date from four variables in SPSS

Self-taught at SPSS here. Need to know the appropriate syntax to recode four DATE variables into one, based on which would be the latest date. I have four DATE variables in a dataset with 165 cases:

wnd_heal_date
wnd_heal_d14_date
wnd_heal_d30_date
wnd_heal_3m_date

And each variable may or may not contain a value for each case. I want to recode a new variable which scans the dates from all four and only selects the one that is the latest and puts it into a new variable (x_final_wound_heal_date).

How to use the SELECT IF function for this purpose?

Solution

  • select if function selects rows in the data, and so is not appropriate for this case. What you can do is this instead:

    compute x_final_wound_heal_date = 
    max(wnd_heal_date, wnd_heal_d14_date, wnd_heal_d30_date, wnd_heal_3m_date).
VARIABLE LABELS   x_final_wnd_heal_date 'Time to definitive wound healing (days)'. 
VARIABLE LEVEL   x_final_wnd_heal_date(SCALE). 
ALTER TYPE x_final_wnd_heal_date(DATE11).

    This will put the latest of available date values in the new variable.