The following statement was included with the tables showing CRC raw counts and expanded estimates from a 2016 report I received. I hope it might help answer your questoin.

"Halibut CRCs, Puget Sound

Raw totals are the fish recorded on the returned sample cards. Our in-sample group comprises 25% of the issued cards. Typical return rates are in the 40% range, so these numbers come from about 10% of the issued cards. The expanded estimates are calculated by expanding the raw catch out to the total issued cards. We do NOT correct for non-response bias, so these estimates are likely high; however, then can be used to track trends.

For the sake of simplicity, the Puget Sound numbers exclude areas other than 5, 6,7, and 9, and also exclude catch from outside the catch season months. The coastal counts include all months. We do not make review phone calls on halibut reports as we do for salmon or steelhead."