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Glossary

adopters

first-time purchasers of a product or first-time users of an innovation. See adoptions.

adoptions

First-time purchases of a product or first-time uses of an innovation In the Bass Model the number of adoptions is equal to the number of adopters, therefore these terms are used interchangeably. See adopters.

Bass Model differential equation (DE)

Since the left side is f(t), the DE equation is also

Expressed in terms of adoptions

where a(t) is adoptions at time t and A(t) is cumulative adoptions at time t.

See Which Bass Model Equation Should I Use?

Bass Model differential equation solution

See Which Bass Model Equation Should I Use?

Bass Model discrete forms

A discrete form of the Bass Model is required for the real world because adoptions (sales to first time buyers) are measured in discrete time intervals (e.g., years).

See Which Bass Model Equation Should I Use?

Bass Model discrete form - F(t)-based form (Srinivasan Mason form)

In this form, f(t) is expressed in terms of F(t) as

.

See Which Bass Model Equation Should I Use?

Bass Model discrete form - f(t)-based form

See Which Bass Model Equation Should I Use?

Bass Model principle

See Bass Model Home Page

category

See product category

discrete time

In discrete time, time (usually denoted t) can only take specific values such as 1, 2  3, ... or 1.5, 2.5, 3.5, ... or -9.2, -7.3, -4.1 and other specific values. Discrete time does not mean that time can take only integer values (e..g, 1, 2, 3, ....) but integer values are normally the case in the Bass Model.

F

The Bass cumulative probability distribution (CDF).

The probability that a potential adopter will have adopted  the product at t.

Also, the portion of the potential market that will have adopted at time t.

In continuous form,

.

This can be simplified using

ab

to obtain

big_F_2

and further simplified using

to get

big_F_3.

f(t)

The Bass probability distribution (PDF).

The probability that a potential adopter will adopt the product at time t given that they have not yet adopted.

also, the portion of the potential market that adopts at time t.

In continuous form,

.

This can be simplified by using

to obtain

and further simplified using

to

which rearranges to

.

M

Bass Model parameter M represents the potential market size, which is the maximum number of adopters that will ever adopt the product

p

Bass Model parameter p

peak in adoptions

to do

penetration

to do

product

Used interchangeably with product category.

to do

product category

to do

q

Bass Model parameter q