Make regular backups of your data. In multiple locations.

There was a fire in my building at UW-Madison a few years ago. An article in the paper quoted a grad student who despaired, “My only copy of my dissertation is in there!” Don’t let that happen to you.

Consider using a formal version control system, like git, though it’s not the best for data files. If you want to get a bit fancy, maybe look at dat.

Keep all versions of the data files, so that if something gets corrupted (e.g., you accidentally type over some of the data without noticing it until much later), you’ll be able to go back and fix it. Before you start inserting more data, make a copy of the file with a new version number: file_v1.xlsx, file_v2.xlsx, …

When you’re not actively entering data, and particularly when you’re done entering data, write-protect the file. That way, you won’t accidentally change things.

• On a Mac, right-click on the file in Finder and select “Get Info”. In the menu that opens, there’s a section at the bottom on “Sharing & Permissions”. Click on “Privilege” for yourself and select “Read only”.

• In Windows, right-click on the file in Windows Explorer and select “Properties”. In the “General” tab, there’s a section at the bottom with “Attributes”. Select the box for “Read-only” and click the “OK” button.

Back up your data!

Next up: Use data validation to avoid data entry mistakes.

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