Norm and Yardstick

Norm went first, to show the how-often.

She held up her tally-book at an alarming notice: "FOUR foxes seen near the burrow this week!" "Four foxes sounds scary," Norm said. "So first: how OFTEN are foxes usually seen near the burrow?" She flipped to her counts. "Most weeks: three or four. Four foxes is a completely NORMAL week." She looked at Fen. "See? Knowing the base rate already helps — four isn't unusual." Then she paused. "But suppose the notice said 'four foxes' and I checked my book and four IS normal — I'd relax. Good. But what if the notice said 'a fox was seen FOUR HUNDRED FEET away'? My tally-book counts how OFTEN foxes appear — it says nothing about whether four hundred feet is CLOSE or FAR." She glanced at Yardstick. "How OFTEN is my question. But some scary numbers aren't about how often — they're about size and distance. For those, I need him."

Fen considered. "So YOUR question handles 'how many, how often'... but not 'how big, how far.'"

"Only the how-often," Norm agreed. "Half the sizing-up. The other half is his."

Then Yardstick took over, to show the compared-to-what.

He laid his reed against the same notice's other claim: "A fox was seen FOUR HUNDRED FEET from the burrow!" "Four hundred feet sounds close and scary," Yardstick said. "So: compared to WHAT?" He stretched a long wing. "Four hundred feet is right-next-door for a FLYING hawk. But for a fox padding through thick grass, four hundred feet is a long, slow way off — plenty of warning." He looked at Fen. "See? The comparison tells you four hundred feet is actually FAR, for a fox. That's my question — compared to what." Then he folded his wing. "But suppose the notice just said 'a fox was seen.' My reed measures size and distance — but 'a fox was seen' has no size to measure. The real question there is how OFTEN foxes are seen at all." He glanced at Norm. "For the how-often, I need her."

Fen looked from the meerkat to the heron. "So HIS question handles 'how big, how far, compared to what'... but not 'how often.' And YOUR question handles 'how often'... but not 'compared to what.'"

"Two partners," Yardstick said. "A scary number usually needs both."

Then Norm and Yardstick sized up the whole alarming notice TOGETHER, and Fen finally saw a scary claim shrink to its real size.

The notice roared: "DANGER! FOUR foxes seen this week, one just FOUR HUNDRED FEET from the burrow!" Fen's heart pounded. But Norm asked her question — "How OFTEN, usually? Four foxes a week is... completely normal, three or four is every week." And Yardstick asked his — "Compared to WHAT? Four hundred feet, for a slow-padding fox, is a long, safe way off with lots of warning." And together, with both partners supplied, the terrifying notice deflated into what it really was: a normal number of foxes (Norm's half), at a safe distance (Yardstick's half). Nothing alarming at all. Fen's heartbeat slowed.

"OH," Fen breathed. "It only sounded like DANGER because the notice gave the numbers with NEITHER partner — no 'how often,' no 'compared to what'! And giving it both makes it ordinary!"

"That's it," Norm said. Alone, her how-often caught the 'four foxes' but not the 'four hundred feet.' Alone, Yardstick's compared-to-what caught the distance but not the frequency. But together — how often AND compared to what — they gave the scary numbers both missing partners, and the numbers found their true, ordinary size. "I tell you how often it usually happens," Norm said. "And I tell you what to measure it against," Yardstick said. "Both partners," they said together, "and a number built to scare you finds its real size instead."

Fen tried it on a small scary claim — "TWO owls, within a hundred wingbeats!" — asking both: "How often, usually? (Two owls is a normal night.) Compared to what? (A hundred wingbeats is far, for a walking shrew.)" — and the claim shrank to nothing. "I gave it both partners," Fen said, "and it stopped being scary."