Skip to main content
Find a member Join

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.

Major contractors and clients ‐ including Balfour Beatty, Costain, HS2 JV, Mace, Multiplex and Skanska ‐ have already adopted the Common Assessment Standard. This means that these main contractors will specify the CAS for their supply chain, but that the supply chain should only need to obtain one CAS certification to tender for work with them. There is growing support from buyers in both 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 >

Recognised Assessment Bodies and CAS schemes

Common Assessment Standard Achilles CHAS** Constructionline
Desktop BuildingConfidence Gold Desktop Audit
(formerly BC CAS Desktop)
CHAS Premier CAS Constructionline Gold
Site-Based BuildingConfidence Gold 1 Day Audit
(formerly BC CAS Site Assessment)
CHAS Premier CAS Assured Constructionline Platinum

**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 >

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 they will 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.

Some questions answered...


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. Data sharing makes it easier for public sector and commercial buyers to specify CAS Certification from any Recognised Assessor. Several of the largest main contractors are already supporters and they will be specifying the CAS.

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. 

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 >