The total amount of all broadcasts of a medium. It is a good sign if this value is higher than the expected amount.
The sum of all expected amounts of all broadcasts of a medium. New broadcasts are added to the database at different times. Those broadcasts that have been in the database for a long time have an advantage over recently added broadcasts. To get around this bias, we calculate the number of "impressions" - how often a broadcast was viewed by our users. Based on the impressions, we calculate the expected value according to the following formula:
expected(broadcast) = impressions(broadcast) * average
average = total_amount / total_impressions
The number of all broadcasts of a medium in the database. Obviously, the actual amount and especially the expected amount correlates with this value. If many new broadcasts of a TV or radio station have been added to the database, this value is higher compared to the expected amount.