The Numbers Guy examines numbers in the news, business and politics. Some numbers are flat-out wrong or biased, while others are valid and help us make informed decisions. Carl Bialik tells the stories behind the stats, in daily updates on this blog and in his column published every other Friday in The Wall Street Journal. Carl, who holds a degree in mathematics and physics from Yale University, also cowrites The Daily Fix, a sports column on WSJ.com. He welcomes your comments at .

The Numbers Guy
copyright © 2012 Dow Jones & Company, Inc.
Carl Bialik examines the way numbers are used, and abused.

In Implant Controversy, Sure Numbers Are Scarce
Without comprehensive tracking of breast implants and other devices, authorities can't be sure of failure rates, nor of which implants pose how much risk to recipients.
The Crime That’s Counted
Criminologists look to homicide as a reliable benchmark of overall crime rates, yet it isn't tracked with the same definitions nor reliability throughout the world.
Private Equity’s Job Record
What a new study of private equity firms' impact on jobs at target companies says and doesn't say about the industry.
Elections Change Rules, Face Unforeseen Consequences
The Republican Party, and the Oscars, changed their voting rules for this season. The consequences of such shifts aren't always clear.
When Polls Turn Up the Wrong Number
Public knowledge of crucial numbers is low, according to surveys. Researchers offer some explanations, and question whether the widespread innumeracy matters much.
A World Full of Alarming Traces
As a U.K. radio report highlights, traces of frightening materials are ubiquitous in our modern, interconnected world. How much danger these pose is another question.
When to Use Scary Stats
Advertisers who seek to raise awareness about -- and raise funds to fight -- illness find that there isn't a hard-and-fast rule about when to cite frightening prevalence and mortality figures.
How Speedy Are High-Speed Internet Lines?
Governments begin fact-checking broadband operators claims of upload and download speed, with results varying by carrier and by country.
Pollsters Go Mobile
As more Americans ditch their landlines and rely on cellphones, some polling firms are following. Others may be risking their accuracy in surveys about upcoming elections.
Seeking the Most Expensive Products
Which chocolates, hot dogs and bathtubs are most expensive? Companies jockey to claim them even as few line up to buy.