Emerging and high-growth product categories present exciting opportunities for firms as they put their bets on which markets will reap the biggest return for them. Forrester's market sizings and forecasts help navigate the unknown landscape of these new markets, bringing primary research, analysis, and ideas together into a quantitative picture of scale and timing. To help understand our forecasts — and to help market researchers use this powerful tool — we describe Forrester's business-to-business (B2B) forecasting methodology based on a logistic or S-curve methodology.