Data Deficient: How Many Studies Does It Take to Prove a Bird Isn't There?

The Spotted Pinyon Jay's official conservation status, as assigned by our Initiative, is "Data Deficient. Extremely Deficient."

We stand by that rating. We are, if anything, worried it is too generous.

But a question keeps coming up, usually from the back row of a meeting: if study after study finds no Spotted Pinyon Jays, at what point does "we haven't found it" become "it isn't there"?

Our analysts have spent a great deal of time on this. Here is what they found. Or rather, did not.

One Study at a Time

The first study is always the most exciting. Hopes are high. Binoculars are clean.

The first study finds no Spotted Pinyon Jays. This is not a problem. "One study is just one study," said the Chief of Avian Uncertainty. "It may have been the wrong week."

By the second study, a pattern begins to form. By the fifth, the pattern is very clear. By the tenth, the pattern has its own filing cabinet.

Every study finds nothing. But each study also concludes, in its final paragraph, that "further study is needed."

Our Senior Habitat Speculation Officer calls this "the renewable resource of uncertainty." It never runs out. It powers entire careers.

The Math

At the request of a resident who asked not to be identified, our team attempted to calculate exactly how many studies it would take to prove the bird is not there.

The resident's reasoning was simple: each study that finds nothing should make us a little more confident the bird is absent.

Our analysts agreed in principle. Then they ran the numbers, using a formula the Director of Unconfirmed Ornithology wrote on a napkin. The napkin has since been laminated.

The result: the number of studies required is "one more than we have done so far."

The formula has been checked many times. It is remarkably consistent. No matter how many studies are completed, the answer is always one more.

Absence of Evidence

There is an old saying in science: absence of evidence is not evidence of absence.

There is a newer saying, coined by our Coordinator of Public Comment after a long evening session: absence of evidence is not evidence of absence, unless you have looked really, really hard, in which case it kind of is, but please don't quote me.

We quote the Coordinator here anyway, with permission, because they have since been promoted.

When Is Enough Enough?

Satire aside, the question is real and important. Good science does not prove a negative with total certainty, but well-designed surveys, repeated over time, can tell us with growing confidence that something is very unlikely to be there. At some point, reasonable people move on.

That point arrived for the Spotted Pinyon Jay a long time ago. We simply did not attend that meeting.

Meanwhile, real data on the real Pinyon Jay is not deficient at all. Long-running bird surveys show the species has declined significantly, which is exactly the kind of signal that helps direct conservation where it is needed.

The Spotted Pinyon Jay is fictional. This post is satire. The real Pinyon Jay is not.