NEC3, ECC Clause 65.2 - Assessment of Compensation Event is not revised

Dear All

According to NEC3, ECC Clause 65.2, the assessment of a compensation event is not revised if a forecast upon which it is based is shown by later recorded information to have been wrong.

In the case, if measurement/quantities (from Drawings, not forecast) of an implemented CE based on PM’s assessment (assessment based on subcontracts’ unit rates) is found incorrect, can the Project Manager change the assessment and what basis?

In other case, can the Project Manager change the method of valuation for an implemented CE which is assessed by PM’s assessment and what basis?

W K Yip

Whilst you are correct in citing the inability of the PM to revisit a previously implemented CE, the PM can change their decision on that assessment (for whatever reason) and issue a new CE under 60.1 (8). However, the contractor has the right to assess this themselves (62.2) prior to the PM providing their own assessment for a reason stated in 64.1. Furthermore, the assessment cannot reduce the Prices under this method as stated in clauses 63.2, 63.10 & 63.11.


The Project Manager nor Contractor can change an Implemented Compensation Event. Once the CE is Implemented, it is Implemented, and the only recourse for either Parties to change that assessment is via Adjudication / ADR.

My interpretation of your question is that the Contractor has quoted a CE which the Project Manager has rejected and assessed themselves, and it turns out their assessment is incorrect which you are challenging.

If this is correct, i would suggest advising the Project Manager of their error, and agree a way to correct the assessment via a new Compensation Event or Instruction, as again, and as you rightly say, there is no mechanism to change an Implemented Compensation Event.

Dear All

Thank you for your advice.
So quotation or PM’s assessment could not be change once a CE is implemented disregarding whether the mistake is incorrect forecast or incorrect measurement



The only instance where you can revisit a CE is when an Assumption made by the Project Manager (61.6) proves to be incorrect (60.1 (17)). But even then, you’re not reopening an existing Compensation Event, you’re creating a new one which is assessed on its own merits.

Again, i think a sensible conversation with the Project Manager is needed.