From the New York Times:
In photojournalism, the subject is considered more important than the aesthetics of the image. While clarity, composition and exposure have always been taken into account, it is news value that drives the profession. But in the 1980’s and 90’s, photographers like James Nachtwey and Gilles Peress established distinct visual styles in their coverage of war-torn regions like Bosnia and Chechnya; the way they observed their subjects, discerned in what they chose to shoot and where they stood, added new layers of information to the editorial image.
Here.