DUBIOUS DATA MADE HEADLINES IN 1997

Each year at this time, the Statistical Assessment Service, a Washington
research organization that abbreviates itself STATS, releases its annual
list of the most absurd, amusing and alarming science and statistical news
stories of 1997.

Herewith, a few of the group's choices. The full list may be found on the
World Wide Web at www.stats.org.

YOUR CHILD'S BRAIN ON DRUGS

Teen Drug Use

Dips Down

- -- Associated Press, Aug. 7

Drug Use Rising Among Young Adults

- -- Associated Press,

a few hours later the same day

These dueling headlines were based on the same National Household Study on
Drug Abuse survey, which found that illicit drug use among the young was
up, alarmingly in some cases. The AP's first headline and the story
accompanying it illustrate the perils of data slicing -- focusing on only
one segment of the study population -- and a failure to appreciate a
concept called statistical significance. According to the study, young
people between ages 12 and 15 did report a slight decline in the use of
marijuana.

But another age bracket, dubbed "young adults" 18 to 25, showed a
significant increase in marijuana use. More importantly, the drop among
younger people was not statistically significant, which means there's a
fair chance that the apparent decrease was due to sampling error.

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