Math Tools: Using Percentages to Your Advantage

Sarah Beth Costello
April 27, 2009

Graphic by Sarah B. Costello

Graphic by Sarah B. Costello

MATH – it’s a small word, yet one that causes discomfort and even irrational fear in the hearts of many. For some math is a dreaded area of academia that seems relatively unimportant, especially for those pursuing a career in journalism.

Why would a reporter need to understand percentages, fractions or statistics right? Well it just so happens that basic math knowledge is very important. In fact, good math skills can make all the difference between a successful and not-so-successful career.

Dr. Kathleen Woodruff Wickham is the author of “Math Tools for Journalists” and understands the importance of math skills as a journalism professor at the University of Mississippi.

Journalists frequently take advantage of statistics. Statistics can strengthen an article, add clarity and specific information. But flawed or skewed data can severely hurt the reputation of a journalist. This is why it is important for journalists to possess an understanding of math in order to avoid basic mistakes.

Journalists often depend on other sources for data, but it is important to understand conversions as well.

For example:

The Red Hat Society had an annual budget of $1500 in 2006. Due to a donation, the annual budget was raised to $3500 in 2008. What percentage increase was the budget?

New figure: $3500
Old figure: $1500

3500 – 1500 = 2000
2000/1500 = 1.33 = 13 %

Sometimes, however, you will need to show a percentage decrease. This is also a very simple, yet important, formula.

Due to the recession, Truett Cathy, the owner of Chick-fil-a, decided to reduce his annual donation to Samaritan’s Purse from $10,000 to $3650. By what percentage was his donation reduced?

3650 – 10,000 = – 6350
– 6350/10,000 = – 63.5 %

Wickham points out that the context is always required so that readers can understand the numbers. Though $1 million dollars sounds like hitting the jackpot, “if that $1 million is just one percent of a city’s annual payroll, the figure doesn’t seem as big,” said Wickham. Calculating the percentage will enable your readers to understand your article and will put everything into perspective as well.

For example:

The North Carolina Train Museum spent $257,456 repairing a 19th century locomotive. The entire budget of the museum is $1 million. What percentage of the entire budget did the repairs consumer?

257,456/1 million = 25.7 %

Calculating Stats in Sports Writing

Have you ever seen a baseball card or attended a baseball game? Ever notice frequently used acronyms like “ERA” or “RBI” or heard the terms “batting average” or “slugging percentage?” Sports stats can get a little confusing, but as any baseball fan will attest, they are very important.

For instance, the batting average indicates the consistency of players to hit the ball. The average incorporates at-bats, subtracts the walks and the “number of times the batter was hit by the pitch.” Earned Run Average (ERA) measures a team’s score against a specific pitcher. The formula for this particular measurement is ERA = R(27/ip).

In this case, “R” represents the number of runs scored when a particular pitcher was on the mound. “Ip” represents the number of outs made during the pitcher’s time on the mound.

The ‘L’ word (Loans)

Whether making payments on a car, apartment or house, many consumers make monthly payments. Most people use advanced calculators when figuring out these detailed figures. But there is a formula, which ensures accuracy from journalists.

Example:

Bojangles bough a building for $75,000. It financed the entire amount at 5 percent for the period of 12 years. What is the monthly payment?

A = [$75,000 x 1 + .005) 120 (power) x .005]/[(1 + .005) 120 (power) – 1]

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1 comment
  1. Janna said:

    Nice outline of the chapter. Applying yourself diligently to the math readings is vital because it helps you reinforce and internalize the standard methods for the use of numbers in good journalism. Keep it up – excellent!

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