Adstock & Saturation Curve (Concept Demo)

Adstock is Simon Broadbent's 1979 concept that advertising effect decays over time rather than switching off instantly — each week's 'effective' weight is this week's GRPs plus a decayed share of last week's. Saturation is the separate, older idea that response curves flatten as spend rises — you can't buy reach you've already bought. Production media mix models (see the patent reference below) fit both curves to real sales-response data; this demo runs the same two-step transform on numbers you enter, using a simple exponential saturation curve, so you can see directly why doubling weekly spend never comes close to doubling effective reach.