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FM 1098 is not “a high-crime, high-drug area”: This crime map reflects Waller County data
from 2013 to 2017 collected by Baltimore-based crime data aggregator SpotCrime, which
sources data from local police departments.
More on the dilemmas caused by haystack searches: Middle-aged women, in most countries, are
encouraged to get regular mammograms. But breast cancer is really rare. Just under 0.5 percent
of women who get a mammogram actually have the disease. Looking for breast cancer is
therefore a haystack search.
Epidemiologist Joann Elmore recently calculated just what this means. Imagine, she said, that a
group of radiologists gave a mammogram to 100,000 women. Statistically, there should be 480
cancers in that 100,000. How many will the radiologists find? 398. Believe me, for a task as
difficult as reading a mammogram, that’s pretty good.
But in the course of making those correct diagnoses, the radiologists will also run up 8,957 false
positives. That’s how haystack searches work: if you want to find that rare gun in someone’s
luggage, you’re going to end up flagging lots of hair dryers.
Now suppose you want to do a better job of spotting cancers. Maybe getting 398 out of 480 cases
isn’t good enough. Elmore did a second calculation, this time using a group of radiologists with
an extra level of elite training. These physicians were very alert, and very suspicious—the
medical equivalent of Brian Encinia. They correctly identified 422 of the 480 cases—much
better! But how many false positives did that extra suspicion yield? 10,947. An extra two
thousand perfectly healthy women were flagged for a disease they didn’t have, and potentially
exposed to treatment they didn’t need. The highly trained radiologists were better at finding
tumors not because they were more accurate. They were better because they were more
suspicious. They saw cancer everywhere.
If you are a woman, which group of radiologists would you rather have read your mammogram?
Are you more concerned about the tiny chance that you’ll have a cancer that will be missed, or
the much larger probability that you’ll be diagnosed with a cancer you don’t have? There’s no
right or wrong answer to that question. Different people have different attitudes toward their own
health, and toward risk. What’s crucial, though, is the lesson those numbers teach us about
haystack searches. Looking for something rare comes with a price.
The author is grateful for permission to use the following copyrighted material:
Photos: Duchenne and non-Duchenne smiles. Reprinted by permission of Paul Ekman, Ph.D./ Paul Ekman Group, LLC.
Photo: “Anger” from Job van der Schalk et al., “Moving Faces, Looking Places: Validation of the Amsterdam Dynamic
Facial Expression Set (ADFES),” Emotion 11, no. 4 (2011): 912. Reproduced by permission of author.
Images: “Rey-Osterrieth Complex Figure,” “Sample ROCF immediate recall drawings from the Pre/Post-stress groups,”
“Sample ROCF immediate recall drawings from the Stress Group,” from Charles A. Morgan et al., “Stress-Induced Deficits
in Working Memory and Visuo-Constructive Abilities in Special Operations Soldiers,” Biological Psychiatry 60, no. 7
(2006): 722–29. Reproduced by permission of Dr. Charles A. Morgan III and Elsevier.
Excerpts from “Edge” [6l.], “Lady Lazarus” [2], “A Birthday Present” [6] from The Collected Poems of Sylvia Plath, edited
by Ted Hughes. Copyright © 1960, 1965, 1971, 1981 by the Estate of Sylvia Plath. Editorial material copyright © 1981 by
Ted Hughes. Reprinted by permission of Harper Collins.
Excerpt from “The Addict,” by Anne Sexton from Live or Die (Boston: Houghton Mifflin, 1966). Reprinted by permission
of SLL/Sterling Lord Literistic, Inc. Copyright by Anne Sexton.
Graphs: “Relation between gas suicides in England and Wales and CO content of domestic gas, 1960–77”; “Crude suicide
rates (per 1 million population) for England and Wales and the United States, 1900–84”; “Suicides in England and Wales by
domestic gas and other methods for females twenty-five to forty-four years old” from Ronald V. Clarke and Pat Mayhew,
“The British Gas Suicide Story and Its Criminological Implications,” Crime and Justice 10 (1988): 79–116. Reproduced by
permission of Ronald V. Clarke, Pat Mayhew, and the University of Chicago Press.
Map: Weisburd Jersey city map from David Weisburd, et al., “Does Crime Just Move Around The Corner? A Controlled
Study of Spatial Displacement and Diffusion of Crime Control Benefits,” Criminology 44, no. 3 (2006): 549–91.
Reproduced by permission of David Weisburd and the American Society of Criminology.
About the Author
Malcolm Gladwell is the author of five New York Times bestsellers: The Tipping Point, Blink,
Outliers, What the Dog Saw, and David and Goliath. He is the host of the podcast Revisionist
History and is a staff writer at The New Yorker. He was named one of the 100 most influential
people by Time magazine and one of Foreign Policy’s Top Global Thinkers. Previously, he was
a reporter with the Washington Post, where he covered business and science, then served as the
newspaper’s New York City bureau chief. He graduated from the University of Toronto, Trinity
College, with a degree in history. Gladwell was born in England and grew up in rural Ontario.
He lives in New York.
Also by Malcolm Gladwell
David and Goliath
What the Dog Saw
Outliers
Blink
The Tipping Point
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