Market segmentation refers to subdividing a larger market into smaller submarkets.Philip Kotler defines, "Market segmentation is a process of identifying groups of buyers with different desires or requirements."Criteria for effectively evaluating the resulting market segment:1) Identifiable and Measurability:The segments must be identifiable so that the marketer can know which customers belong to a segment and which do not.The size, profile, and other relevant characteristics must be measurable in terms of data. It must be possible to determine the values of the variables used for segmentation with justifiable efforts.It is important especially for demographic and geographic variables.2) Relevant size of the resulting segment:The size and the profit potential of the segment must be large enough to economically justify separate marketing activities for that segment.If the resulting segment is small in size then the cost of marketing activities will not be justified.3) Accessibility:The segment has to be accessible and servable for the organization.This criterion refers to the ease of effectively reaching chosen segments with marketing efforts.Some desired segments could be inaccessible due to legal reasons. 4) Substantial:The resulting segments must be substantial to generate required returns.The activities with a small segment could give a biased or negative result.These four are important criteria for effectively evaluating the resulting market segment.Therefore, Perishability is NOT a criterion for evaluating the resulting market segment.Perishability:It is used in marketing to describe the way in which a service cannot be stored for sale in the future.Once served to a customer, the service is totally consumed and could not be delivered to another consumer.