What is the difference between [INPUT MESSAGE] and [ERROR ALERT] in data validation?

[Cschcord]

Hello! I am a business management student currently enrolled in an Excel Course. As part of this course, I've been instructed to post a question on an Excel forum that relates to our coursework.
Currently, we are working on Importing Data, Reviewing, and Finalizing the Workbook, and I am specifically working on data validation at the moment.

So my question is, what is the difference between input message and error alert in data validation? I feel like they do the same thing and I don't understand why they're separate.

Thanks so much in advance! have a great day!

 

[6StringJazzer]

Input Message is displayed whenever you click on the cell. It is a prompt that you can write to tell the user what they are expected to do.

Error Alert is the message to show the user if they enter data that fails the validation test. A good error message will give them an idea of what they did wrong and how to fix it.

Let's say you are expecting the user to enter the day they started their current job. Obviously that cannot be in the future.

Data validation rule: Less than TODAY()+1

Input message in yellow box, error alert in dialog box: