If you wanted to provide feedback to your users that they had entered their date of birth in the wrong format, which visual cue would be best suitable?

Providing feedback to users about an incorrect input format, such as date of birth, is crucial for enhancing usability and ensuring data integrity. The best approach in this case involves showing an error message with the correct format. This method not only informs users about the mistake they've made, but it also provides them with clear guidance on how to rectify the issue.

By including the correct format within the error message, users receive immediate context, which can help them understand specifically what they need to do to comply with the expected input. This proactive approach significantly reduces frustration and allows users to correct their input swiftly, improving the overall user experience.

In comparison, while highlighting the input field in red can draw attention to the error, it does not offer guidance on how to correct it. Similarly, displaying a success message would be misleading, as it incorrectly suggests that their input was accepted. A tooltip could provide helpful information, but it may not be as immediately noticeable as a clear error message that specifically addresses the issue at hand. Therefore, an error message that also states the correct format is the most effective method for guiding users in this scenario.