S T E V E D O I G C R O N K I T E S C H O O L O F J O U R N A L I S M

Math and Data for Business Journalism Students

Math and data

�  Journalism students are terrified of math and think Google answers everything.

�  Business coverage demands… ¡  Good math skills ¡  Good data analysis skills

�  We need to teach them how to use math to analyze data.

Computer-assisted Business Reporting

�  Internet browser �  Spreadsheet: Microsoft Excel �  Database manager: Microsoft Access? �  Statistics: SPSS?

Business math

�  Percentage change �  Compound interest �  Rates �  Consumer price index �  Probability �  Linear regression �  Exotica:

¡  Gini coefficient ¡  H-H index ¡  Benford’s Law

Percentage change

�  Measure change over time

�  NEW / OLD – 1 �  or (new – old) / old � Example: $8 million profit this year, $5 million

last year ¡  8/5 - 1 = 1.6 - 1 = .6, or a 60% increase

� Example: $5 million profit this year, $8 million last year ¡  5/8 – 1 = .625 – 1 = - .375, or a 37.5% decrease

Compound interest

�  Calculates the effect of interest being added to principal over time, thus compounding the return

�  Future_value = present_value * (1 + i)^n �  i = interest rate �  n = number of periods (i.e., 360 for 30 year

mortgage paid monthly) �  Many compound interest calculators on the Web:

¡  http://www.webmath.com/compinterest.html

Rates

�  Allows comparisons between places/companies of different size, or comparisons across time

�  Examples: Accident rates, foreclosure rates �  Example: Jonesville has 50 of 20,000 homes in

foreclosure; Metropolis has 5,000 of 2 million in foreclosure ¡  Jonesville: (60 / 20000) * 1000 = 3 homes per 1,000 ¡  Metropolis: (4000 / 2000000) * 1000 = 2 homes per 1,000

Consumer price index

�  Accounts for inflation; lets you compare prices over time in constant dollars

�  Price_now / cpi_now = price_then / cpi_then �  Get CPI from Bureau of Labor Statistics at

www.bls.gov/CPI/

CPI example: Gasoline prices

� CPI now = 231.3 (October 2012) � CPI in 1965 was 30.8 � Gasoline in 1965 was $0.30 per gallon. � X / 0.30 = 231.3 / 30.8 � X = (231.3 / 30.8) * 0.30 � X = 7.51 * 0.30 = 2.25 � Therefore, gas in 1965 cost the equivalent of $2.25

per gallon in today’s dollars.

Probability

�  Most likely use in business journalism would be to calculate the chances of some event occurring.

�  Also important in understanding p-values in research papers.

�  Example: WSJ calculated the chances of executive stock options being granted at the best possible time and used the results to show that dozens of companies were backdating option grants.

Linear regression

�  Useful for spotting outliers �  Compares how one or more independent variables

affect the value of a dependent variable �  Relationship can be seen in an X-Y scatterplot �  Time-series regression: Time is X-axis

Other business statistics tools

�  Herfindahl-Hirschman Index: used to measure market concentration

�  Gini coefficient: measures inequality in wealth distribution

�  Benford’s Law: pattern of first digits in a collection of numbers can reveal expense account cheating or other man-made patterns.

� Websites your students should know: ¡  Company websites for industries they cover. ¡  Secretaries of State websites for incorporation records.

http://www.nass.org ¡  Hoovers for company and industry information, (but it’s a

pay site). http://www.hoovers.com ¡  Lexis/Nexis. http://www.lexisnexis.com/

Business data

Searching for data

�  Google (use advanced search) �  Google Finance: www.google.com/finance �  Bing �  Wolfram Alpha?

More websites with business data

� Edgar for SEC filings. http://www.sec.gov � The SEC site also contains enforcement data.

http://www.sec.gov/divisions/enforce.shtml � Bureau of Economic Analysis for updated state and

regional economy data. http://www.bea.gov � The Bureau of Labor Statistics has even more

economic statistics. http://www.bls.gov � The Federal Reserve has much information about

monetary policy and banking. www.federalreserve.gov

Still more…

�  Patent and Trademark Office is sometimes useful. http://www.uspto.gov/

�  Don’t forget the U.S. International Trade Commission. http://www.usitc.gov/

�  And the U.S. Census Bureau for demographics. http://www.census.gov

U.S. Census Bureau

�  It’s much more than head counting – here’s just a little of what business journalists can find at census.gov: ¡  Economic Census – local business data collected every five

years. ¡  County Business Patterns. ¡  Minority- and women-owned business data. ¡  Building permits. ¡  Foreign trade exports and imports by state.

Census business data index page

�  http://www.census.gov/econ/index.html

Foreign trade data

�  For example, from the Census Bureau, downloadable from its Web site:

Census data tutorials!

�  http://cronkite.asu.edu/census2010

IRE resources for business journalists

http://store.ire.org/ � The Investigative Reporter’s Handbook: A Guide

to Documents, Databases and Techniques, by Brant Houston, Len Bruzzese and Steve Weinberg.

� Numbers in the Newsroom: Using Math and Statistics in the Newsroom by Sarah Cohen. Part of the IRE Beat Book series.

More IRE resources

�  IRE Resource Center: www.ire.org/resource-center/ �  Why reinvent the wheel? �  More than 2,000 tip sheets from IRE and NICAR

conferences, many on covering the business beat and doing investigations.

�  Searchable database of more than 20,000 stories, both print and broadcast.

More IRE resources

� The NICAR Database Library http://ire.org/nicar/database-library/

� Databases for business journalists: ¡  SEC administrative proceedings. ¡  Federal contracts data. ¡  Home Mortgage Disclosure Act data. ¡  IRS Exempt Organizations. ¡  SBA business loans and disaster loans. ¡  Federal Audit Clearinghouse Database. ¡  Consumer Product Safety data ¡  OSHA Workplace Safety data ¡  Wage and Hour Enforcement

Good math resources

�  Innumeracy, by John Allen Paulos �  A Mathematician Reads the Newspaper, by Paulos �  Precision Journalism (4th ed.), by Phil Meyer �  The Signal and the Noise, by Nate Silver �  Math Tools for Journalists, by Kathleen Woodruff

Wickham �  Cartoon Guide to Statistics, by Larry Gonick �  Statistics Every Writer Should Know (website),

www.robertniles.com/stats/

Excel and web data demonstrations