Formula
Geometric adstock: A(t) = x(t) + θ × A(t-1)
Why it matters
The geometric form adds a fraction of last period's effect to this period's spend. A higher fraction means the effect lasts longer.
Glossary // A / Pharmacokinetics
What is Adstock?
Definition
Adstock is the carryover effect of advertising, where spend in one period keeps influencing results in later periods while fading at a steady rate.