I have a spreadsheet that has the following columns:

Arrival Time Triage Time To ED Time Saw MD Time Discharge Time

I have about 15 people entering data in this worksheet at different times.
There a a few that can't quite get the numbers entered right - example.

The patient will arrive at 10:30 but they may enter a time that they were
taken to the ED at 8:30 - two hours before they are even here!! I have
talked to these people and told them that they need to watch the times that
they are entering and make sure that they are accurate.

Is there a code/way to set the worksheet up so that if they enter a time
that is wrong it won't let them enter. I have tried Validation - time -
allow greater than or = to. That won't work.

Thanks for any help.