Output Specification
A specification defining what the supplier must achieve rather than how; gives suppliers freedom to innovate on method.
Definition
An output specification defines what the supplier must achieve (outcomes, performance levels, quality standards) rather than how to achieve it. The supplier has freedom to propose the methodology, technology, and resource model that delivers the required outputs. Modern UK public procurement increasingly favours output specifications because they support innovation, value for money, and competition on approach rather than commodity input cost. The Procurement Act 2023 encourages output specification where it serves the procurement objectives.
How it works in practice
A strong output specification has three components. First, the outputs themselves: specific outcomes the supplier must achieve, with measurable success criteria. Second, the operating context: constraints the supplier must respect (locations, hours, integration points, security requirements, regulatory compliance). Third, the performance regime: KPIs that will measure delivery against outputs, with thresholds and consequences. Output specifications avoid prescribing inputs (specific products, specific staff qualifications, specific methods) unless those are genuinely necessary; over-prescription removes the supplier's freedom to innovate and effectively converts the procurement back to an input specification with all the cost rigidity that implies. The challenge in writing output specifications is being specific enough that suppliers can price and design the bid without being prescriptive on method. A common pattern is to define hard requirements (outputs that must be achieved at defined levels) and soft requirements (outputs scored on degree of achievement, where suppliers compete on approach). Outcomes-based commissioning (popular in adult social care and children's services) is an extreme form of output specification: the buyer pays for outcomes (people supported into independent living, children achieving permanence in stable placements) rather than service inputs. The KimonBids bid management module helps suppliers map output specifications into structured method statements that connect proposed approach to required outputs.
Common questions
When should buyers use input vs output specifications?
Input specifications work for commodity goods and works contracts where the buyer needs specific products and methods. Output specifications work for services and complex outsourcing where the buyer wants to incentivise innovation and value for money. Many contracts use hybrid specifications: output-led with input minimum standards (staff qualifications, certifications, mandatory tools).
Are output specifications harder for suppliers to bid?
They give more design freedom but require more work to articulate the proposed approach credibly. Suppliers should evidence the connection between proposed methodology and required outputs explicitly, ideally with case study evidence of having delivered similar outputs in similar contexts. Weak output-spec bids paste generic methodology onto unfamiliar requirements; strong ones build the methodology bottom-up from the specific outputs required.
How are KPIs structured for output specifications?
Around the required outputs rather than process metrics. Where an input specification might measure "Number of training sessions delivered per month" (process) an output specification measures "Number of trainees achieving certification" (outcome). Outcome KPIs are typically harder to deliver against and require longer measurement windows but align more closely with the buyer's policy objective.