Final answer:
The important criterion to consider when identifying market segments is the size of the market.
Step-by-step explanation:
The important criterion to consider when identifying market segments is the size of the market. Market size refers to the total number of potential customers or the total revenue that can be generated from a particular group of customers. It helps businesses determine the potential profitability and viability of targeting a specific segment.
For example, if a company is considering targeting a market segment of young adults aged 18-24, they would need to understand the size of this age group in the overall population and their purchasing power. This information would guide their marketing strategies and product offerings for this segment.