Marketing Mix Modeling (MMM) – Attribution with Adstock and Diminishing Returns

This Excel approach implements a simplified Marketing Mix Model directly in a spreadsheet using adstock transformations and diminishing returns (Hill function). Transform raw media spend with adstock (recursive formula) to capture carryover, then apply a non-linear saturation curve (e.g., spend^alpha/(spend^alpha + beta^alpha)) per channel. Fit coefficients via Solver (minimize SSE between predicted and actual sales), or export prepared dataset for regression in Python/R. Build a scenario tool to reallocate budget across channels and compute projected sales uplift and ROI. Include diagnostics (residual plots, contribution shares) and regularization to prevent overfitting. This is pragmatic for marketers who need attribution insights without immediate BI tooling.