Merge/Update or Append data files

 

Append data files:

 

Append refers to adding more records. The data files that you want to pool together should have common variables.

Empower(R) will first search for common variables among the listed of data files. And only keep these common variables from each data file. If there are no common variables, no data will be pooled.

 

Merge/Update data files:

 

Merge/Update refers to adding more variables or update old variables with the data from new data file. The data files that you want to merge together should have common subject identification (ID variable).

This function could be used to: add variables, update variables, and exclude (select) subjects from original data.

 

Output ID options for each data:

 

Output ID options are 1,0, or . (default).

1 means output ID should be in the data;

0 means output ID should not in the data;

. Means output ID could be or not be in the data;

Following tables is used to illustrate how output IDs options works. In the table there are 4 IDs in 4 data files.

ID

Current data (A)

Data (B)

Data (C)

Data (D)

1

yes

Yes

Yes

No

2

yes

Yes

Yes

Yes

3

No

No

yes

Yes

4

yes

Yes

no

Yes

 

ID=1, in data A, B, C, not in D;

ID=2 in data A, B, C, D;

ID=3 in data C, D, not in A, B;

ID=4 in A, B, D, not in C.

 

If ID output options for data A was set as 1, then ID 1, 2 and 4 will meet this requirement.

If ID output options for data B was set as 1, then ID 1, 2 and 4 will meet this requirement.

If ID output options for data C was set as 1, then ID 1, 2 and 3 will meet this requirement.

If ID output options for data D was set as ., then all ID will meet this requirement.

 

So ID 1 and 2 will meet all the above requirements and will be output.

 

 

A screen shot of sample input window:

 

In this sample, ID output options for regis1 is 1, for all others are ..

 

A sample output window: