Procurement Essentials is a new series of articles to help you overcome common hurdles, understand key concepts, and make your life as a buyer of everyday goods and services easier.

Published 16 November 2021

Last updated 16 November 2021

It’s the most important document within the tender process. Here are our top tips on how to write a specification.

What is a specification?

In a procurement context, a specification can be defined as a ‘statement of needs or requirements’. It provides a detailed description of the goods or services a supplier is expected to supply during the lifetime of the contract. It is also a record against which suppliers can be measured and is legally binding. 

It should encourage fair and open competition within the marketplace and help suppliers make informed decisions on whether to bid. 

Why is it important to get it right?

Specification writing is an important and underrated skill. A supplier shouldn’t need to make assumptions – a good specification must include all the right information to enable them to cost up goods or services accurately so a customer can compare bids on a like for like basis. Your specification mustn’t mislead suppliers or give them false expectations.

Mistakes with specifications can result in poor service and a waste of public money. You might even breach procurement rules and face legal challenges.

What types of specifications are there?

There are two main types of specification – the input and the output specification.

Before you start, be clear on which one you are writing.

Input specifications

An input specification sets out exactly what is required. 

Typically, the solution required by the contract is set out in full and no (or little) further development is needed. This type of specification gives a clear and rigid framework within which the supplier’s performance can be monitored. However, the lack of flexibility means that there is little or no incentive for the supplier to innovate or improve service delivery. 

Over-specifying can also add cost to the product or service – make sure that the ‘gold-plated’ option is what you really need.

Output specifications

Output specifications define only the outcomes (or outputs) that are required by the contract, that is, what the supplier is expected to deliver. Output specifications can offer suppliers greater flexibility for developing innovative solutions. 

Remember that you do still need to include the relevant standards or legislation, for example health and safety requirements that will apply to the goods or services you are procuring. 

How to write a specification – top tips

Take time to get it right. A good specification is created through the planning and research undertaken before writing. 

Start by agreeing a timetable and roles and responsibilities. Who is going to write it? Ideally it should be led by someone with relevant skills and experience such as a procurement practitioner or technical specialist. Most local authorities have procurement specialists who might be able to advise smaller local organisations without in-house expertise.

Engage as early as possible with key stakeholders for input (e.g. customers, internal and external technical experts) to help draft and develop it. Make sure that any market engagement carried out to develop your specification is transparent, open and fair. This means asking potential suppliers the same questions and giving each one similar information.

Don’t restrict competition by including bias that favours a particular supplier. Avoid referring to brands, trademarks or any specific processes that are particular to suppliers in the marketplace. 

Break down your objectives and then organise your specification into component parts with a clear and logical flow. Include an introduction, then background, scope of services and detailed requirements. Make sure you incorporate information on your brand values so that suppliers can consider and adopt these. Think about what your requirements are – separating into ‘must haves’ and ‘nice to haves’ – and write in terms of outputs. For example, as part of a contract to renovate a hospital car park you might want the contractor to install signage for users. 

Your specification could specify precise features and dimensions: where the signs should be placed, dimensions, types of paint, background colour, font type, materials to be used etc.

Alternatively, your requirement could be less detail-focused, requiring that signs are prominently placed, provide simple clear information, are readable from a reasonable distance and made from durable materials. In other words, the contractor worries about the detail, you focus on what you want the signage to do.

In practice, your specification might include a bit of both. The point is to think about how the specification you need to write will match the outcome you’re looking for. Don’t assume a supplier can read your mind.

Make your specification as enforceable and measurable as possible. Be clear what success and failure looks like. If you want to specify for something using exact numbers (for example, time limits, productivity rates etc) be sure that what you are asking for makes sense, is realistic, attainable and can be verified. Use positive and directive language such as ‘the supplier shall ensure that the project delivers x, y and z.’ 

Always write in plain English and avoid technical jargon unless you’re sure a person reading it will understand what you’re asking for. Avoid empty filler terms such as ‘leverage’, ‘world class’, ‘synergise’ and ‘game changer.’

There are many laws governing the procurement of supplies, services and works for the public sector. At the very least you should be aware of the basic fairness principles that apply to public procurement policy

You may also need to consider the impacts of policy and legal issues relating to cyber security,  GDPR, carbon net zero, prompt payment of suppliers and social value. They probably won’t all apply in every procurement but it’s important to check.

Finally, review, review, and then review again. Do several sense checks before you send out.

Remember, get it wrong and you won’t get what you want.

Find out more

More information and guidance for public and third sector buyers, as well as full details of all of our commercial agreements, can be found in the latest CCS digital brochure.