Frontline, a Public Broadcast Service (PBS) public affairs program, is known for covering tough, controversial issues that advertisers might not want to sponsor. PBS is funded by viewers and donors, not advertisers. For more than a year, ESPN collaborated with PBS's Frontline on the production of a two-part program titled League of Denial: The NFL's Concussion Crisis. The program was based on a book written by two of ESPN's investigative reporters. ESPN suddenly ended its affiliation with Frontline, less than two months before the program was scheduled to be shown and a week after a lunch meet- ing between the NFL Commissioner and ESPN executives. ESPN has a $15.2 billion contract with the NFL and has been accused multiple times of allowing its sports interests to take precedence over its news division.

Why ESPN might have a conflict of interest between sports news journalism and sports broadcasting? Conduct an online search to learn whether Frontline and ESPN have journalistic guidelines they follow. If so, describe them. Please add the reference.