Date Difference

[Nandini-2]

I have a data set with two different dates - date1 and date2 (both in
ADATE10 format).  I need to see how many in how many records date1 and
date2 is less that 02/28/2006 and in how many records date1 and date2 is
less than 03/31/2007.

Using an IF statement (IF fte_3mnth_delq_dt <=2006/02/28) is not getting
any results.

I'd appreciate any suggestions that you might have.

Thanks

[Norton, John]

Hi Nandini,

Try the code below (which you'll need to edit specific to your dataset, and which also assumes there are no missing values for your date fields);

COMPUTE x = (date1 < DATE.MDY(2,28,2006) AND date1 < DATE.MDY(2,28,2006)).
COMPUTE y = (date1 < DATE.MDY(3,31,2007) AND date1 < DATE.MDY(3,31,2007)).
VALUE LABELS
   x 0 'Not Earlier than Feb. 28, 2006' 1 'Earlier than Feb. 28, 2006'
  /y 0 'Not Earlier than March 31, 2007' 1 'Earlier than March 31, 2007'.
FREQ x y.


I hope that helps,

John Norton
SPSS Inc.

-----Original Message-----
From: SPSSX(r) Discussion [mailto:[hidden email]] On Behalf Of Nandini
Sent: Tuesday, May 22, 2007 1:21 PM
To: [hidden email]
Subject: [BULK] Date Difference
Importance: Low

I have a data set with two different dates - date1 and date2 (both in
ADATE10 format).  I need to see how many in how many records date1 and
date2 is less that 02/28/2006 and in how many records date1 and date2 is
less than 03/31/2007.

Using an IF statement (IF fte_3mnth_delq_dt <=2006/02/28) is not getting
any results.

I'd appreciate any suggestions that you might have.

Thanks

[Richard Ristow]

At 02:20 PM 5/22/2007, Nandini wrote:

>I have a data set with two different dates - date1 and date2 (both in
>ADATE10 format).  I need to see how many in how many records date1 and
>date2 is less that 02/28/2006 and in how many records date1 and date2
>is less than 03/31/2007.
>
>Using an IF statement (IF fte_3mnth_delq_dt <=2006/02/28) is not
>getting any results.

See John Norton's fix, of course. The key point is, SPSS does not have
date constants (more's the pity). The expression "2006/02/28" is the
arithmetic expression (2006/2)/28=1003/28=35.82142857.

As per what John said, the only (reasonable) way to get a date value is
to build it from the date functions. For the date 2006/02/28, use
DATE.MDY(02,28,2006). (SPSS doesn't have DATE.YMD, a minor but
sometimes annoying omission.) So, for your IF statement, use

IF fte_3mnth_delq_dt <=DATE.MDY(02,28,2006)

By the way, dates are numeric variables, and as for all numeric
variable, comparison does not in any way depend on what their formats
are.

Going beyond that, you may want a single variable for your tests. Logic
like this (not tested):

NUMERIC   DateCats (F2).
VAR LABEL DateCats 'Range for date1 & date2'.
VAR LABEL DateCats
     1 'Both <02/28/2006'
     2 'Both <03/31/2007'
     3 'One >=03/31/2007'.

COMPUTE   DateCats = 3.
IF  MIN(date1,date2) < DATE.MDY(03,31,2007) DateCats = 2.
IF  MIN(date1,date2) < DATE.MDY(02,28,2006) DateCats = 1.

FREQUENCIES DateCats.