The market segmentation process has two steps. The first step identifies market segments by partitioning the total market into well-defined segments. A market segment is well-defined if is satisfies these four characteristics:
It is measurable in terms of population size, purchasing power, and product usage frequency
It is accessible – it can be reached and served by the brand's marketing capabilities
It is substantial in market size to be worth developing a marketing program for it
It is differentially responsive to one, some, or all of the marketing inputs as compared to other segments