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The Common Assessment Standard

The rollout of the Common Assessment Standard (CAS) aims to significantly reduce the duplication of time, effort and resources experienced by suppliers during prequalification.

A growing list of major contractors and clients ‐ including Balfour Beatty, Costain, HS2 JV, Mace, Multiplex and Skanska ‐ is adopting the Common Assessment Standard. These main contractors will specify the CAS for their supply chain, and the supply chain should only need to obtain one CAS certification to tender for work with a buyer who has adopted the CAS.  Over time, the CAS may also make more inroads into the commercial and public sector.    

The Common Assessment Standard is an industry‐agreed question set with two levels of certification ‐ desktop and site‐based. Assessment is delivered by any one of three Recognised Assessment Bodies. For companies that employ fewer than 10 employees and have a turnover below £1.8 million or a balance sheet total less than £1.8 million, the assessment questions are applied in a proportionate way.

The Common Assessment Standard Question Set can be viewed here >

ECA's Common Assessment Standard Manual was last updated in July 2024 and will be reviewed in 2025.

Recognised Assessment Bodies and CAS schemes


Common Assessment StandardAchillesCHAS**ConstructionlineCQMS
DesktopBuildingConfidence Gold Desktop AuditCHAS Elite (CAS)Constructionline GoldSafety Scheme Premium
Site-BasedBuildingConfidence Gold 1 Day AuditCHAS Elite (CAS) AssuredConstructionline PlatinumSafety Scheme Elite

**ECA members’ special deal (CHAS only): free ‘first time SSIP’ component of a CAS assessment plus 27% discount on the remainder, and an ongoing 27% discount on CAS assessment. 15% off site-based CAS audit. Terms and Conditions apply. View the full offer here >

It is vitally important that Member’s consider the specific assessment requirements of their buyer/client base before selecting a particular CAS assessment body, noting that many buyers/clients are still not signed up to the CAS.

Data sharing

Data sharing enables contractors and clients to obtain key PQ data on their suppliers from any Recognised Assessment Body, regardless of which one carried out the certification to the Common Assessment Standard. This means that those buyers who have adopted the CAS should no longer need to specify a particular assessment body for their supply chain. The data is updated in ‘real time’, and it will be shown where a company’s certification has lapsed if they have not provided updated information. Data is shared only where a company has provided their consent.

Please see the following Build UK note on data sharing >

Some questions answered...


Yes, but please note that those buyers and clients who are not yet signed up to the CAS may still have assessor preferences.

If they are signed up to the CAS, yes. They will require you to achieve the CAS, but it should not matter which Recognised Assessor gives you your certificate. Other buyers who are not signed dup to the CAS may still have particular assessor preferences, though the industry will be looking to persuade as many as possible to sign up.

Not right away – the CAS will take time to move more widely through the industry. However, the CAS offers many cost and efficiency benefits to buyers and suppliers, so it should be increasingly attractive to buyers of all kinds. ECA will also work with the industry to encourage buyers to accept supplier CAS certification from any Recognised Assessor. 

This still depends on your clients and buyers. It is therefore vital that any choice you make about your CAS assessor takes into account what your client or buyers currently insist on. Those buyers signed up to the CAS (see the Build UK website) should now accept CAS assessment from any assessment provider, though it is worth checking this before your assessment. However, others may still insist on a particular assessment provider. If you encounter the latter at your request we will provide these client/buyers with information about the possibility and benefits of recognizing the CAS from any assessment body.

Yes, and an ECA ‘CAS manual’ provides practical information to small and medium sized ECA Members on how to engage with the various CAS questions.

The three Recognised Assessment bodies will set their own charges (ECA Members can obtain a 27% discount on CAS assessment through the CHAS assessment route). CAS assessment may cost more (or possibly not, depending on your assessor) but suppliers should expect to save time as PQQs increasingly align with the Common Assessment Standard, and save money as they find they can discard some of their multiple PQQ certifications.  

Applications are already in the pipeline, though all new assessors must meet the Build UK assessor criteria. 

Yes, the questions in the SSIP (health and safety) assessment are also asked in the CAS, so you will already have met this key part of the CAS assessment. This will save you time and may also save you money.    

For more information on the Common Assessment Standard please also see the Build UK website >