Police shootings in the United States

Journalists in the United States are doing the counting for the number of people killed each year by the police, as official figures are incomplete or non-existent. Tim Harford reports and asks why black people are disproportionately killed.
Also, the anti-vaccination movement that appears to be gaining ground in India, and why we seem to be getting smarter with every passing decade. Mike Williams reports on the Flynn Effect, which measures rising IQ scores across the globe.

(Photo: Police officers stand guard at a barricade following the sniper shooting in Dallas. Credit: AFP/Getty Images)