The New York Times‘ Brian Stelter examines the diverging interests of the evening news programs today, noting the three newscasts “are shaking up conventions that stretch back 50 years” in search of unique identities:

On some days, the differences at 6:30 p.m. are substantive; on a Thursday in December, CBS led with Iran’s capture of a United States drone surveillance aircraft, NBC opened with an investigation into the mishandling of soldiers’ remains, and ABC with the mysterious shooting of a police officer at Virginia Tech.

On other days, they are stylistic; on Tuesday, as the Iowa caucus commenced, ABC led with a piece on Rick Santorum’s surge, CBS led with a news-making interview of Newt Gingrich, and NBC with a recap of the day’s campaigning.

There are differences in tone, as well. Scott Pelley of CBS evokes anchors of yesteryear while ABC’s Diane Sawyer radiates empathy for her subjects. These are “eye of the beholder” factors, as Brian Williams of NBC put it. “We are different people,” he said, “so naturally we all bring a different ‘voice’ to our on-air writing and our delivery style.”