This article applies to:
E-Merge does allow two (or more) files with the same Subject number and Session number to be merged. E-Merge does NOT allow the exact same data file to be merged into a single merged file more than one time. A unique identifier is associated with each data file that tells E-Merge whether or not the data is different.
For example, a participant runs a study as Subject-Session 1-1, and the data is merged into a data file. If an attempt is made to merge the data file again, E-Merge examines the unique identifier, determines that it is exactly the same data, and automatically overwrites (i.e., update) the existing data in the group data file.
In another example, 2 participants are run, but the researcher mistakenly assigns both Subject-Session 1-1. The Subject and Session numbers are the same, but the files do not contain the same data. When a merge is attempted on the data, a prompt occurs stating that there is a duplicate Subject and Session number. The researcher is then given the opportunity to continue or abort the merge operation. If the researcher continues, there will be two sets of data in the merged data file that have the same Subject and Session number. We recommend modifying the Subject and/or Session numbers in E-DataAid in this case. If the researcher aborts the merge operation, the Subject/Session values in the original data file can be modified and then the merge operation can be performed again. The only difference between these two options is the result of which data file shows the modifications.
By automatically overwriting identical data files, E-Merge prevents anyone from "creating" data by merging multiple times. By allowing duplicate Subject/Session numbers in the same data file, E-Merge safeguards against loss of data, and allows the user to correct a mistake.