1.   And Fox is sending viewers away from its local news in many markets during the vital period during which ad rates are set.

2.   Ad rates are based on six-month circulation averages.

3.   Ad rates are based on viewership.

4.   Ad rates rise during the peak campaign season as a torrent of political ads heats up the competition for air time.

5.   Ad rates are determined by viewership as demonstrated by Nielsen ratings.

6.   Advertisers are angry instead because Hearst is making the extremely unusual move of lowering circulation while increasing ad rates.

7.   Affiliates of the networks use the local ratings in the four-week period to set ad rates for coming months.

8.   But February sweeps, when viewer totals help determine ad rates, is gimmick time for TV series.

9.   But last year the company decided to capitalize on its strong position by raising ad rates.

10.   Controlling several popular stations in one market means companies can lift their ad rates because advertisers will pay more to reach wider audiences.