Final answer:
A core competency in the resource-based model refers to a unique strength or advantage that is central to a firm's strategy, difficult for competitors to imitate, and offers a durable competitive advantage.
Step-by-step explanation:
In the resource-based model of above-average returns, a core competency is something that provides a unique strength or advantage possessed by a firm that is central to its strategy and competitive success. Core competencies are part of what makes a company successful in focusing on one or a few products, giving it a competitive edge over others that may offer a wider range of products but with less specialization.
Unlike a temporary competitive advantage, core competencies are expected to be durable and difficult for competitors to imitate, providing a sustainable competitive advantage. They are not just tangible assets; they can also include intangible assets like brand reputation, proprietary technology, or unique expertise in a certain domain.