Calculating Dates from a single variable

[Justin Blehar]

All,

I'm having trouble calculating a date difference from my data set and any help would be greatly appreciated. I apologize if this is a simple question but I can't seem to make it work.

I'm working with a data set in which individuals were administered 3 different measures at various time points. I'm able to use the date and time wizard to calculate the time difference between measures. Now I need to create sets for each individual and compare the time difference between sets. In order to do this I need to calculate time differences within a single variable. For example:

ID    Measure 1
1        2007
1        2008
1        2010
2        2006
2        2012
3        2008
3        2009

Is there a way to do this without going through each participant as this would take quite some time (I'm working with days, months, years)? For some participants I have more than just two time points for when the measure was administered but I can filter these out to have only two scores each per measure if necessary.

Thanks so much!

V/R

Justin

[David Marso]

Take a look at the LAG function also CREATE and SHIFT VALUES commands.
Other useful commands SPLIT FILE and DO IF.
Review try some stuff and repost any remaining issues.

Justin Blehar wrote

All,

I'm having trouble calculating a date difference from my data set and any help would be greatly appreciated. I apologize if this is a simple question but I can't seem to make it work.

I'm working with a data set in which individuals were administered 3 different measures at various time points. I'm able to use the date and time wizard to calculate the time difference between measures. Now I need to create sets for each individual and compare the time difference between sets. In order to do this I need to calculate time differences within a single variable. For example:

ID    Measure 1
1        2007
1        2008
1        2010
2        2006
2        2012
3        2008
3        2009

Is there a way to do this without going through each participant as this would take quite some time (I'm working with days, months, years)? For some participants I have more than just two time points for when the measure was administered but I can filter these out to have only two scores each per measure if necessary.

Thanks so much!

V/R

Justin

[Rich Ulrich]

I don't find it obvious what it is that you are trying to obtain.

But I think that the first step might be -- Use Lag to get the
time difference between records, and set it to missing if the
Lag on ID does not show a match. 

That gets you one or more times for a person. 

You can use Aggregate to get one record per person, which can
contain the average or the total -- if that is what you are looking for.

If you want something else, please try again.

--
Rich Ulrich

---

Date: Thu, 17 Jan 2013 06:40:28 +0000
From: [hidden email]
Subject: Calculating Dates from a single variable
To: [hidden email]

All,

I'm having trouble calculating a date difference from my data set and any help would be greatly appreciated. I apologize if this is a simple question but I can't seem to make it work.

I'm working with a data set in which individuals were administered 3 different measures at various time points. I'm able to use the date and time wizard to calculate the time difference between measures. Now I need to create sets for each individual and compare the time difference between sets. In order to do this I need to calculate time differences within a single variable. For example:

ID    Measure 1
1        2007
1        2008
1        2010
2        2006
2        2012
3        2008
3        2009

Is there a way to do this without going through each participant as this would take quite some time (I'm working with days, months, years)? For some participants I have more than just two time points for when the measure was administered but I can filter these out to have only two scores each per measure if necessary.

Thanks so much!
...

[David Marso]

IOW:  If you really expect any sort of solution you would best take a few minutes and cobble out an AFTER version of what the data should look like!  Yeah, there are a number of gifted telepaths in this group but ...
--

Rich Ulrich-2 wrote

I don't find it obvious what it is that you are trying to obtain.

But I think that the first step might be -- Use Lag to get the
time difference between records, and set it to missing if the
Lag on ID does not show a match.  

That gets you one or more times for a person.  

You can use Aggregate to get one record per person, which can
contain the average or the total -- if that is what you are looking for.

If you want something else, please try again.

--
Rich Ulrich

Date: Thu, 17 Jan 2013 06:40:28 +0000
From: [hidden email]
Subject: Calculating Dates from a single variable
To: [hidden email]







All,



I'm having trouble calculating a date difference from my data set and any help would be greatly appreciated. I apologize if this is a simple question but I can't seem to make it work.



I'm working with a data set in which individuals were administered 3 different measures at various time points. I'm able to use the date and time wizard to calculate the time difference between measures. Now I need to create sets for each individual and compare
 the time difference between sets. In order to do this I need to calculate time differences within a single variable. For example:



ID    Measure 1

1        2007

1        2008

1        2010

2        2006

2        2012

3        2008

3        2009



Is there a way to do this without going through each participant as this would take quite some time (I'm working with days, months, years)? For some participants I have more than just two time points for when the measure was administered but I can filter these
 out to have only two scores each per measure if necessary.



Thanks so much!

...