Hi,
The profiles are checked for data completeness when a Member adds the category [[Category:Suggestions_-_Include_Profile_Completeness]] to their profile.
These suggestions reflect that the status buttons in the top data fields for parents, locations, dates are not set. Please see more information on the Profile Completeness Suggestions Group page and the individual suggestion pages linked.
You can go to the EDIT tab, and the top of any profile shows the EDIT DATA section. This is where you see the radio buttons: certain, uncertain for father and mother. For dates and locations, there are a few more buttons.
These are easy and intermediate difficulty level suggestions, and you can check that the sources verify the information, not only that the fields have parents' names, or birth and death have dates and places. If they are correct, you click the appropriate button.
I hope this helps and enjoy CAT weekend.