When your product manager is researching the market, she has a choice between using hypotheticals and actuals . When interviewing a prospective customer, a product manager who uses hypotheticals asks such questions as: Would you be willing to buy a product that does x, y, and z? If I were to offer you a product that does x, y, and z, how much would you be willing to pay for it? How often would you use a product that does x, y, and z? In contrast, a product manager who uses actuals: Asks what the prospective customer does currently instead of using the product. Determines how much the prospective customer spends to accomplish her goals without using the product. Puts actual product or demos into the prospective customer's hands and determines whether she uses it. Both hypotheticals and actuals are helpful. Hypotheticals are notoriously unreliable , however. To the extent possible, a product manager should favor actuals when researching the market.