How polling works and what it says about America
A new CBS News Battleground Tracker poll puts the Democrats in a better position than Republicans to gain control of the House in November's midterm elections, but many contests are still considered toss ups. Analyzing poll numbers is the specialty of Anthony Salvanto, CBS News director of elections and surveys. He joins "CBS This Morning" to discuss the new book, "Where Did You Get This Number? A Pollster's Guide to Making Sense of the World."