Page 51 - Statistics for Dummies

Chapter 3: Taking Control: So Many Numbers, So Little Time
Uncovering misleading statistics
By far, the most common abuses of statistics are subtle, yet effective, exag-
gerations of the truth. Even when the math checks out, the underlying sta-
tistics themselves can be misleading if they exaggerate the facts. Misleading
statistics are harder to pinpoint than simple math errors, but they can have a
huge impact on society, and, unfortunately, they occur all the time.
Breaking down statistical debates
Crime statistics are a great example of how statistics are used to show two
sides of a story, only one of which is really correct. Crime is often discussed
in political debates, with one candidate (usually the incumbent) arguing that
crime has gone down during her tenure, and the challenger often arguing that
crime has gone up (giving the challenger something to criticize the incum-
bent for). How can two candidates make such different conclusions based on
the same data set? Turns out, depending on the way you measure crime, get-
ting either result can be possible. 35
Table 3-1 shows the population of the United States for 1998 to 2008, along
with the number of reported crimes and the crime rates (crimes per 100,000
people), calculated by taking the number of crimes divided by the population
size and multiplying by 100,000.
Table 3-1 Number of Crimes, Estimated Population Size,
and Crime Rates in the U.S.
Year No. of Crimes Population Size Crime Rate per 100,000 People
1998 12,475,634 270,296,000 4,615.5
1999 11,634,378 272,690,813 4,266.5
2000 11,608,072 281,421,906 4,124.8
2001 11,876,669 285,317,559 4,162.6
2002 11,878,954 287,973,924 4,125.0
2003 11,826,538 290,690,788 4,068.4
2004 11,679,474 293,656,842 3,977.3
2005 11,565,499 296,507,061 3,900.6
2006 11,401,511 299,398,484 3,808.1
2007 11,251,828 301,621,157 3,730.5
2008 11,149,927 304,059,784 3,667.0
Source: U.S. Crime Victimization Survey

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