Posts Tagged ‘Statistics’

Arrest Rates

Following the arrest of Aaron Hernandez, who played tight end for the New England Patriots, a Facebook posted the CNN screen cap above. If you ask a member of the general public how the arrest rate in the NFL compares to that of other sports, or even the country as a whole, they might guess that it is higher, not lower. This is a good example of the difference between raw numbers and statistics and is an important part of the information literacy that students should learn in research methods and statistics courses. Exploring the numbers in a bit more depth (and ignoring the fact that the type of crime, which could easily influence perceptions, is not noted), we can see where misconceptions in the general public might come from.

Major League Baseball has 30 teams and each team has 25 players on its active roster, with up to 40 players signed at any given time. Assuming that these statistics are per year (another good question to ask!), if 2.1% of MLB players are arrested that means that 15.75 (for a 25-player roster) or 25.2 (for a 40-player roster) players would be arrested each year out of 750 or 1200 total players, respectively.

The National Basketball Association has 30 teams and each team has 15 players. If 5.1% of NBA players are arrested in a given year, that results in 22.95 players arrested out of 450 players. As you can see in the table above, this is above the national average. David Stern, the NBA’s commissioner, has famously tried to clean up the league’s image by enforcing a dress code since the beginning of the 2005-06 season.

The National Football League has 32 teams and each team has 53 players, more than twice the active roster of MLB teams and more than three times the number of players on an NBA team. If 2% of NFL players are arrested in a given year, this means that 33.92 players will be arrested out of 1696 total players. A more in-depth exploration of the rate of arrest for NFL players compared to the general population is available here.

If each arrest leads to a news story, it is easy to see how the general public could think that NFL players are getting arrested at a higher rate than their counterparts in other professional sports. Looking at statistics, however, reveals the truth that the large rosters of NFL teams that lead to more media coverage of arrests. A discussion of an easily-accessible topic like this might lead into a more detailed exploration of the selective coverage of certain types of crime by the media, leading to public perceptions about the rate of crime among various race and social class groups.

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In class when talking about commonly held beliefs that are not actually true, we discussed a reading stating that the majority of people on welfare are not, in fact, African American.  One student revealed another commonly held belief about researcher bias by asking, “Is the author black?”

No, the author is not black and, beyond that, race does not influence one’s ability to read a statistical table.

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