That's a correct understanding of specificity. That would imply the correct rate is closer to 22% than 30%, as of the 64 positives out of 200, we would expect

That's a correct understanding of specificity. That would imply the correct rate is closer to 22% than 30%, as of the 64 positives out of 200, we would expect roughly 20 of those to be false positives. (So the remaining 44/200=>22%). Article says there are 40k residents and 39 deaths. If 22% of 40k are infected => 8800 infected. 37/8800 implies .42% IFR, broadly consistent with figures elsewhere, especially given that there is a lag time for deaths. (Which will cause the IFR to increase.) Any bias due to selection etc would basically decrease the denominator on that calculation, increasing the IFR. (This is all just back of napkin, based on numbers in the article, please check my calculations.)