You may find yourself in the scenario where it appears data is missing from the Data Views even though you just saw the same information showing the day before.
In this case, someone removed the option Red from the option list associated to this element.
The data isn't lost, as they key_value for the selected option is still stored in the database. An export of any data feed (Excel in this example) demonstrates the value "red" still exists for record ID 6.
If you export any of the data feeds then you will see the key_value being returned. The easiest way to fix is to add the option back into the list and make sure the option's key_value matches the historical values in the table. The second sceario is when an entire option list is deleted. The solution is the same as above where the list just needs to be recreated using all they kay_values already stored in the DB.
Again, this only affects the output of the Views. No data is lost in the process.