Daypart — how the broadcast day is divided and priced

A daypart is a named block of the broadcast day that is sold as a unit, because the audience inside it is consistent enough to price as one thing. Airtime is bought and sold by daypart before it is bought by programme.

The blocks

Television usually divides the day into early morning, daytime, early fringe, prime time, late fringe and overnight; prime is the most expensive because it carries the largest and broadest audience. Radio divides it differently, around when people travel: morning drive, midday, afternoon drive, evening and overnight — and radio's two drive-time peaks are its prime, which is why a radio rate card looks nothing like a television one.

Why it is the unit of pricing

A daypart is a shorthand for an audience. Weekday daytime reaches a different composition from Saturday prime, and the difference is stable enough week to week that a rate card can be written against it. That is what makes the block sellable in advance: the buyer is not buying a programme, they are buying a predictable audience at a predictable cost per rating point.

It is also how a plan is built. A campaign chasing reach spreads GRP across dayparts to hit more people fewer times; a campaign chasing frequency concentrates them. Which slots are open in each block is the seller's avails picture.

Where it gets complicated

Daypart boundaries are not universal. They differ between markets, between television and radio, and between broadcasters in the same market — and an agency comparing two sellers whose «daytime» starts an hour apart is comparing two different things. A plan that does not normalise them produces a cost comparison that quietly favours whoever defined the block most generously.

In OpenMediaLogic dayparts, rate cards and coefficients belong to the broadcaster that set them, so a multi-channel plan compares slots on audience and price rather than on whose definition of prime is wider. See also radio-specific selling.