Quality and economical aspects of software development are strictly related. Adaptability, as a feature of quality, fosters reuse and the resulting economies of scale. Domain analysis is an effective way to improve adaptability. Yet domain analysis is expensive. To reduce the cost of domain analysis without reducing its effectiveness, we use a set of metrics to measure adaptability during design, i.e., when the cost of improving adaptability is still low. The measures are based on interfaces and assume an object-oriented software development.