When a data file is delivered in CVS or in Excel format and when it is converted into a software specific data table (e.g., SAS data), it is very important to check if ID and time variables are accurately converted. If data are delivered to you regularly and periodically, check if SAS (or other […]
Especially when data are manually entered, you must open the dataset and look at it closely to understand it and spot signs of irregularity.
Whe merging data A and B and if A and B has variables that happen to have the same variable name, one of them will be deleted. For example, if A has "GPA" meaning individual-level GPA and if B has GPA meaning school-level GPA, one of them will be deleted after the merge.