Do the Math: A Basic guide for using numbers in stories

Adopted from former IRE training DirectorDavid Donald with additions by Ron Nixon

The Truth About Numbers!

• Figures don’t lie, but liars figure—Mark Twain.

Innumeracy

• No math required by my j-school.

• Math ignorance as badge of honor.

• We’ve got our nerd.

• My source will give me the numbers we need.

• Numbers are hard, solid, cold facts.

Numeracy

• Numbers are a summary of the real world.

• Many numbers often are a guess.

• Many numbers often are an opinion.

“Building a Sense of Scale”

• Population of City, County, State and Country

• Average Household Income

• Size of the U.S. Economy

• City, County and State Budget

Numbers v. words• No more than two or three numbers in a

paragraph.

• No more than one, maybe two, paragraphs in a row with numbers.

• Dates, time, spelled-out numbers count.

• Memorize common numbers on your beat. Think is this number up or down, big or small.

Numbers v. words

• Round off – and then maybe round off some more.

• Learn to convert to simple ratios to keep your numbers small.

• Always double-check your math answers. No, better triple-check.

Use Devices from Everyday Life

• “About the size of a football field”

• “The equivalent of pouring a teaspoon of water in a lake.”

• “Three times as high as …….”

Numbers v. words

• The editor’s question – Does this number make sense?

• So … When all the above fails, numbers belong in graphics – bar charts, tables and – at last resort – a bulleted break-out box.

Graphics• Take your graphic artist or graphic reporter

to lunch.

• Do your calculations and bar charts in Excel, then export to Adobe Illustrator or Freehand.

• Learn some principles of good graphics to have quality conversations with your graphic folks.

Resources

• Google “misleading graphs” http://www.google.com

• Get, read, study, live with Edward Tufte’s The Visual Display of Quantitative Information

http://www.edwardtufte.com/tufte/

More Resources• Damned Lies and Statistics—Joel Best• A Mathematician Reads the Newspaper—

John Allen Paulos• 200% Of Nothing A.K. Dewdney• Inumeracy—John Allen Paulos• Math Tools for Journalist—Kathleen Woodruff

Wickham• How to Lie With Statistics—Darrell Huff

Finally …

• Essential: Sarah Cohen’s Numbers in the Newsroom http://www.ire.org/store/books/math.html