Bass Diffusion Model

Overview

The Bass model (1969) describes how new products are adopted through two forces: innovation (external influence, coefficient p) and imitation (internal/word-of-mouth influence, coefficient q). The resulting adoption follows an S-curve whose shape is entirely determined by p, q, and market potential m.

When to Use

• Forecasting adoption trajectory for a new product or technology
• Estimating time-to-peak-sales and total market penetration
• Calibrating marketing spend between advertising (p) and word-of-mouth (q)
• Comparing diffusion patterns across product categories or markets

When NOT to Use

• Repeat-purchase or consumable products (Bass models first adoption only)
• Markets with strong network effects requiring explicit network models
• When no analogous product data exists and p/q cannot be estimated