Performance Document Eligibility disappears in the new year/ Where to go for data related questions?

Summary:

Performance Document Eligibilities are disappearing in previous years. Where can we go to find reasons why the data is disappearing from reports?

Content (required):

We report on the performance campaign overview using Performance Document Eligibility Real Time to see if a worker is eligible for the campaign and the status of their performance document if they have started it. I've noticed in previous years the number of documents found in this subject area drops drastically (from ~20k to ~300).

Does something happen to the eligibility records for a performance document when a new campaign begins? If this isn't the forum for data related questions like this, where do we go?