Input specification vs output specification
Traditional specifications are ‘input specifications’. They are prescriptive, that is, they describe in detail the products, materials and work (the inputs) required by a contract. Typically, the development of the solution required by the contract is complete and no (or little) further development is required by the supplier. The specification is considered to be a ‘closed specification’.
Prescriptive input specifications give the client certainty about the end product when making investment decisions, but place a greater burden on them to ensure the product has been thoroughly considered, developed and described. They tend to be used where a very specific end result required.
Output specifications define only the outcomes (or outputs) that are required by the contract, that is, what it will enable the client to do. They are open specifications that do not attempt to address how those outputs might be achieved. For example, an output specification might require the provision of a space for teaching 30 primary pupils, but it would not specify the nature of the space, the types of doors and windows etc. The standard for what is required might be defined, for example, by reference to performance targets.
It is argued that output specifications can get the best value from the supply team by allowing them to adopt innovative solutions to the client's requirements and reduce whole-life costs rather than simply developing the client's pre-conceived solutions at the lowest price.
For more information see: Output-based specification.
[edit] Related articles on Designing Buildings Wiki
- Briefing documents.
- Feasibility studies.
- Final specifications.
- Insulation specification.
- Outline specification.
- Output specification
- Output-based specification.
- Performance specification.
- Prescriptive specification.
- Procurement.
- Service level specification.
- Specification.
- Tender documentation.
- Tender process.
Featured articles and news
Twas the site before Christmas...
A rhyme for the industry and a thankyou to our supporters.
Plumbing and heating systems in schools
New apprentice pay rates coming into effect in the new year
Addressing the impact of recent national minimum wage changes.
EBSSA support for the new industry competence structure
The Engineering and Building Services Skills Authority, in working group 2.
Notes from BSRIA Sustainable Futures briefing
From carbon down to the all important customer: Redefining Retrofit for Net Zero Living.
Principal Designer: A New Opportunity for Architects
ACA launches a Principal Designer Register for architects.
A new government plan for housing and nature recovery
Exploring a new housing and infrastructure nature recovery framework.
Leveraging technology to enhance prospects for students
A case study on the significance of the Autodesk Revit certification.
Fundamental Review of Building Regulations Guidance
Announced during commons debate on the Grenfell Inquiry Phase 2 report.
CIAT responds to the updated National Planning Policy Framework
With key changes in the revised NPPF outlined.
Councils and communities highlighted for delivery of common-sense housing in planning overhaul
As government follows up with mandatory housing targets.
CIOB photographic competition final images revealed
Art of Building produces stunning images for another year.
HSE prosecutes company for putting workers at risk
Roofing company fined and its director sentenced.
Strategic restructure to transform industry competence
EBSSA becomes part of a new industry competence structure.
Major overhaul of planning committees proposed by government
Planning decisions set to be fast-tracked to tackle the housing crisis.
Industry Competence Steering Group restructure
ICSG transitions to the Industry Competence Committee (ICC) under the Building Safety Regulator (BSR).
Principal Contractor Competency Certification Scheme
CIOB PCCCS competence framework for Principal Contractors.
The CIAT Principal Designer register
Issues explained via a series of FAQs.