Over the past decade, the commercial estimate has gone up and the research estimate has gone down by about the same amount. These changes cancel each other out when we’re averaging the two.

The average of 9 and 11 is 10. The average of 8 and 12 is 10. The average of 5 and 15 is 10.

Easy to miss detail: the commercial estimate measures the average tons of cod caught by any given commercial vessel (per unit of effort), not the total tonnage of fish caught by all the vessels. The commercial estimate going up means each vessel is catching more cod (per unit of effort), not that more cod are being caught total.

To support a judgment about accuracy, the stimulus would need an anchor point in the actual stock of cod. Instead, we only have information about 1) how the estimates are obtained, and 2) what their recent outcomes have been.

(D) dies immediately at the word “should,” which attempts to draw a value judgment from the stimulus’ purely descriptive claims.

As discussed in (A), our information from the past decade indicates that the official estimate hasn’t changed much in that time. As for the years prior to that, we only have information about how the two estimates compared to one another, not whether either or both of them were increasing or decreasing.