This document provides instructions and examples for calculating and reporting percentages and percentage changes. It defines key terms like percent, explains how to calculate a percent of a whole, and demonstrates how to calculate percentage increases or decreases when comparing two numbers over time. Examples include calculating the percentage of males in a class and the percentage increase in new voter registrations between two election cycles.

1. Using Numbers to Report TrendsA Lecture

2. Keep your C.H.I.N. UpContext: Why is this story important now?Human Element: Give us a quote.Impact: How does this affect your reader?News: Who? What? When? Where?

3. Let’s Add Some Numbers

4. Definition of PercentPercent means per hundred.If you leave a 10% tip, you’ve given the server a dime per each $1 of food.

5. How to calculate percentOf the 600,000 residents of Baltimore, 300,000 are African American.What percent is that?Part/whole X 100% = percentSo, 300,000/600,000 = 50%

6. Now you try…Of the 24 people in this class, 6 are men.What percentage of the class is male?

7. The answerPart/whole *100 = percentage6/24 * 100 = 25%

8. How to change a percent into a regular number…Forty percent of the 500 survey respondents said they will vote for Sen. Barack Obama. Whole x percent = part500 X 40% = 500 x 0.40 = 200

9. How to calculate a percentage changeThis year, the number of new voters has increased dramatically. Last election cycle, 200,000 new registrants surfaced. This year, 300,000 new registrants signed up.(New Value-Old Value) ÷ Old Value X 100(300,000-200,000) ÷ 200,000 x 100 = ?

10. The Answer(300,000-200,000) ÷ 200,000 x 100 = ?The change is 50%

11. The most important thing to remember…There is a difference between a percentage and a percentage point.For instance, if we say, “Barack Obama would like to raise taxes on upper-class Americans, from 10% to 20%...”That is a change of 10 PERCENTAGE POINTS. (20-10 = 10)What is the percentage increase?

12. Let’s Hear How the Pros Do It

13. Now you try…Find this statistic:The number of new voters in your home state this election cycle.The number of new voters last election cycle.Calculate the percentage increase/decrease.Calculate the percentage point change.