An Excel problem

Someone sends you a file with company and county. The county is obviously wrong on some of them. What do you do? You have a column called “Original County” with their data. This is never changed. Then you have a column called “Corrected County”. Then you copy the data in the “Original” column into the “corrected” column. Then you edit the “Corrected” column. In step form:

1. Create a column called “Original Data”.
2. Consider locking these cells and protecting the sheet.
3. Copy the column called “Original Data” to a new column, and call it “Corrected Data”.
4. Do all your editing, changing, and correcting in the column labeled “Corrected Data”. Never change anything in the column labeled “Original Data”.

Conceptually, what we are doing here is creating an informal audit trail of our work. If we or another person comes back to this work in a week or a month or a year, we can quickly figure out what was done.