The reason, he says, is because the reach curve flattens at higher gross rating point levels.
Thus, a brand can be advertised for more weeks.
In the hypothetical example below, reducing GRPs by one-third, from 100 to 67, reduces reach by only one-fifth, from 50 to 40.
With fewer dollars needed to buy those GRPs per week, a marketer can stay in media for a longer time.
"You can achieve a greater total effect by reducing the weight and running more weeks," he says.