Others (Hester, 1971) have combined

Others (Hester, 1971) have combined interview with content analysis of
input and output news. Some have analysed only the news flow, comparing
what stories editors received with what stories are transmitted (Cutlip,
1954). From imbalances in selection, inferences are drawn concerning the
news values of gatekeepers or their institutions at any stage of the news flow
from wire service to newspaper. Such research has concluded, for instance,
that gatekeepers tend to reduce the proportion of news from the countries of
the South, and to select negative rather than positive news (Peterson, 1981).