WHAT WE REPORT
The purpose of this chart is to show you how often you use different fields when creating object records. We show you the % population of fields, grouped in ranges for clarity, in the last 10,000 records for each object.
For instance, for the Contact object we can see that about 45% of all fields were never used when creating records. These might be custom fields that nobody is using.
ACTIONS TO TAKE
Ideally, you would want your bars to be as fully green or yellow as possible as this indicates that all your fields (system, standard, and custom) are regularly used when creating records and therefore they are useful.
If you spot red or grey areas it means that there are some fields that are either rarely used or never used when creating records. You should investigate whether you really need these fields. But don't automatically assume that a field which is not being filled must be deleted - there might be a rare but important business case for using it.
Clicking on any bar will open the Org Model on that object and you can inspect the fields in more detail. You can then extend the analysis sample up to 50 million records to get a better picture.
The Contact object has about 45% of fields that were never used in the last 10,000 records. I might want to investigate whether there are some custom fields that are not needed here that I could delete, or maybe these fields are truly important in which case I should probably make some of them required.