I have an SPSS file that has several variables with some missing data for a number of cases. I have a second file that contains some of that missing data but not a complete set of data for those respective variables. If I merge the files by "adding cases", it creates duplicate cases. Given that there are over 1000 cases in the overall data set, it would take way too long to delete the duplicate cases. Is there a way to insert the missing values from one file to the other without creating a duplication?
Hi
See the following link. its pretty useful.
https://www.yorksj.ac.uk/media/content-assets/schools/psychological-social-sciences/documents/How-to-enter-missing-data-in-SPSS.pdf
Kind regards
1. Sort Dataset in both files by ID
2. Open the first Dataset so that it is the Active Dataset. Then select:
3. Data > Merge Files > Add Variables
4. Highlight the second Dataset and click Continue
5. Select ID from the list of Excluded Variables and move it into the Key Variables box after checking the following options: Match cases on key variables
Now, cases are sorted in order of key variables in both datasets
Good Luck
check this link:
http://www.ats.ucla.edu/stat/spss/modules/merge.htm
The response from Mohamed A Elkoushy is the first half of the process.
If you want the information from variables that are in data set 2 that are also variables in data set 1, you will need to rename the variables you are bringing over, such as by putting an A or a 2 at the end of them.
Once you do that, you will have duplicate variables, not duplicate cases. Suppose the variable with missing data is called MEASURE1 and the duplicate variable that you merged onto your file is called MEASURE1A. If you now would like the available data from MEASURE1A to become part of MEASURE1, you do the following:
1) Compute a new variable MEASURE1COMB = MEASURE1
2) Modify the new variable as follows:
RECODE MEASURE1COMB (MISSING=MEASURE1A) (ELSE=COPY).
EXECUTE.
This way you will still have the original variables but the new variable will have all the available data from both data sets as one measure.
To follow up on Julia B. Smith's response, here is how I did this sort of merge.
I renamed all of the variables in the secondary dataset by appending the names with an additional letter at the beginning. So, if a variable is "var1" I renamed it to "Tvar1" in the secondary dataset.
Then I completed a merge by adding variables. Select the key variable, which in my case was "ID". (Data>Merge Files>Add Variables) When you do the merge, make sure that you only add the renamed variables from the secondary dataset. Exclude the existing variables from the primary dataset during the merge; this way they remain unchanged in the primary dataset and you just add the appended ones.
Then once you have your datasets merged, you can use IF statements to merge the data one variable at a time. For example, using the "pass" variable example:
IF MISS(Tvar1)=0 var1=Tvar1.
EXECUTE.
This command will copy the values from "Tvar1" to "var1" for any cases that do not have missing data for "Tvar1".
I hope this helps someone!
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