Andie Diemer’s Weblog

by Andie Diemer
Nov. 3, 2008

The Language of Numbers

While words and pictures can convey many aspects of a story to the audience, sometimes the use of figures is essential to make an impact and have an article fully make sense. In Kathleen Woodruff Wickham’s text, Math Tools for Journalists, she explains that “journalists committed to accuracy in reporting need to understand the language of numbers — the different forms of numbers, how these forms are used to convey information and appropriate usage for words used in combination with numbers.”

Wickham said it is essential to always check the math of speakers, official reports and budgets to ensure proper calculations are being conducted and nothing is being tweaked to look a certain way. The form of the information and the words that accompany the numbers is also important to pay attention to; the reporter has to digest the information to make it relevant and understandable to the audience.

Tips:

• Spell out single digit numbers
• If a number begins a sentence, it should be rewritten to not do so
• Do the math for your readers
• Limit the amount of numbers used in each paragraph to two or three
• Use fewer for items that can be counted; use less than for mass or time terms
• Use more when talking about greater in quantity; use most when talking about the greatest in quantity

Percentages

When dealing with percentages, it is important to understand several aspects. Percentage increase/decrease is calculated by (new figure – old figure) / old figure.

Percentage of a whole can help to put things into perspective and can be calculated by taking the subgroup / the whole group.

Percentage points differ from percent; to convert a decimal to a percentage, slide the decimal point two points to the right.

Simple/annual interest can be used to compute interest and can be found by taking the principal x rate (ad a decimal) x time (in years).

Compounding interest normally deals with loans and can be tricky. If A = monthly payment, P = original loan amount, R = interest rate, expressed as a decimal and divided by 12 and N = total number of months, then the formula looks like this: A = [P x (1 + R)^N x R] / [(1 + R)^N – 1].

Compounding interest can also deal with loans. If B = balance after one year, P = principal, R = interest rate and T = number of times per year the interest is compounded, then the formula is: B = P(1 + [R / T])^N.

Tips:

• A percent is one one-hundreth of something; one percentage point can be one-hundredth of something as well as something other than one percent
• Principal is the amount of money borrowed; interest is the money paid for the use of money
• “Compounding” means the interest is added to the original principal

Example:

Smith Jackson announces that 2/3 of Elon’s population attended Sarah Palin’s rally. What percentage of the students attended?

Answer:

.67 percent

Statistics

From crime rates to test scores, statistics are also commonly used to relate information from the reader. Journalists have to be extremely cautious when using statistics however, since they can easily be used to manipulate readers. However, there are a few important aspects to understanding statistics.

Mean is the sum of all figures in a group divided by the total number of figures.

The median is the midpoint in the grouping of numbers; to find the median, rewrite the numbers from lowest to highest and then find the number that has the same number of numbers above and below it.

Mode is the number that appears the more frequently in a distribution of numbers.

Percentile is a number representing the percentage of scores that fall at or below the designated score.

To find percentile rank, take the number of people at or below an individual score / number of test takers.

Standard deviation shows how much a group of figures varies from the norm; to calculate this subtract the mean from each score in the distribution, square the resulting number for each score, computer the mean for these numbers and find the square root.

Probability is simply a ratio, to find it, take the total number of whatever number of whatever you’re calculating / by the smaller number x the total number.

Tips:

• The mean is called the average
• Make sure the findings are not preliminary or inconclusive
• Ensure the headline is a fair reflection of the report
• Check to see if there are any other statistical correlations

Example: Find the median

$6,000

$7,000

$8,000

$9,000

$10,000

Answer: $8,000

Federal Statistics

It’s important to know where federal statistics come from and how they can be used as a tool to propel a story.

Unemployment is a common statistic that is released every month by the U.S. Department of Labor and is defined as the percentage of the labor force that is unemployed and actively seeking work. The formula = (unemployed / labor force) x 100.

Inflation and consumer price is measured by the Consumer Price Index and shows the amount of inflation in any given month for either major product groups. To find the monthly inflation rate = (Current CPI – Prior Month CPI) / Prior Month CPI x 100.

Gross domestic product is the value of goods and services produced by a nation’s economy. If C = consumer spending on goods and services, I = investment spending, G = government spending and NX = net exports (exports minus imports), then GDP = C + I + G + NX.

Trade balance is the difference between the goods and services a country exports to foreign countries and those it imports and can be found by taking exports – imports.

Tips:

• Labor force means everybody over 16 who has a job or has looked for one in the past four months
• This excludes people not actively seeking work and those that are institutionalized
• Employed means the person did some work for pay in the week before the survey was taken
• GDP can gauge the direction of the country’s economic activity

Example:

In 2000, American companies exported $6.8 billion worth of computers and important $50.2 billion worth. What was the trade balance in computes?

Answer:

$43.4 billion loss