Value proposition
A value proposition is the specific bundle of benefits a firm promises to deliver to a chosen customer, and the reason they should buy.
If you cannot say in a sentence why a particular customer should choose you, you do not yet have a strategy.
A value proposition is the specific promise of benefit a firm makes to a chosen set of customers: what need it meets, for whom, and why its offer is better for them than the alternatives. It is the bridge between what the firm does and why anyone should care.
Three questions, answered together
A sharp value proposition answers which customers are served, which needs are met, and at what relative price, as a single coherent choice. The three cannot be decided separately. Choosing demanding, quality-sensitive customers implies a different need set and price point than choosing cost-conscious ones. A proposition that tries to serve everyone, meet every need, and win on price at once is not a proposition but a wish.
It implies what you will not do
A real value proposition excludes as much as it includes. Promising unmatched personal service to a premium clientele means declining to be the cheapest, and accepting the cost structure that personal service requires. The exclusions are not a weakness in the proposition; they are what make it deliverable and credible.
From promise to system
A value proposition is only as good as the activities behind it. The promise sets the standard; the firm's operations, people, and choices must actually meet it, day after day, or the proposition becomes a liability that advertises the gap between claim and experience. The strongest propositions are backed by a tailored value chain that makes the promise hard for rivals to copy without rebuilding themselves.
The discipline a value proposition imposes is clarity. State plainly who the customer is, what they get, and why it beats the alternative, and the rest of the strategy has something to be consistent with. Leave it vague, and every downstream choice is unanchored.