The monthly cycle and its actors
The typical mechanics chain four steps. The measurement of what was executed in the period, on the real works and not on the plan. The relación valorada (valued statement), applying the contract rates to those measurements. The certification proper, which the execution director prepares and signs in accordance with their legal function. And the developer's payment under the agreed conditions.
The distribution of roles reproduces the LOE's agent architecture: the contractor proposes and documents, the execution director verifies and certifies, the developer pays. The independence of the central link is the system's guarantee, which is why the practice of negotiating certifications directly between developer and contractor, bypassing the execution direction, weakens exactly the control one pays to have. The complete documentary mechanics of the cycle are developed in the article on works certifications in the quantities and budgets guide.
Certification, contract and reality
The certification lives off two simultaneous references. Backwards, the contract: the agreed unit rates, measurement rules and chapter structure are its grammar, and their quality was decided in the detailed design and the procurement, long before the first month on site. Forwards, the settlement: the series of certifications builds the economic position with which the parties will reach closure, and every badly certified month is a postponed dispute with interest.
Between both references runs the real works, which never coincide exactly with the designed ones. The differences are channelled through the contract's adaptation instruments, approved modifications and new rates for new units, and the discipline consists in processing them as what they are, formal changes with written price and order, instead of letting them sediment as uncovered extra costs the final settlement will have to arbitrate. The control of deviations against the budget, with its own techniques, is developed in the article on cost control and deviations.
| Step of the monthly cycle | Who does it | Document |
|---|---|---|
| Measurement of executed work | Contractor and execution director | Valued statement |
| Checking and approval | Execution director | Signed certificate |
| Approval and payment | Developer | Invoice and transfer |
| Record of modifications | Works director | Order book and agreed prices |
Tracking as an alert system
Well run, the series of certifications is the project's best early-warning instrument. Three monthly readings suffice to govern: physical progress against the plan, anticipating schedule problems; consumption against the budget by chapters, locating deviations where they are born; and the pocket of unformalised works, modifications in process and pending rates, whose size is the best predictor of the settlement's conflict level.
The classic danger signal is not the declared deviation but its absence: the job that certifies months of perfect normality and explodes at the end is, almost always, a job that was badly measured or silenced early. Uncomfortable economic information loses value every month it takes to surface.
Frequent errors
The first is certifying by estimated percentage instead of real measurement, manufacturing a fiction of progress that reality will collect at settlement. The measurement is taken on site and checked against the bill of quantities.
The second is paying for modified works without a formalised order and price, giving up the contractual position exactly when it starts being worth money. The order and the price are signed before execution.
The third is tolerating systematic delays of the cycle, certifications documenting the works of two months ago, turning the alert system into retrospective chronicle. The monthly cycle is respected like any other site milestone.
The fourth is reading the certification only as an invoice and not as information: the developer who files without analysing gives up for free the only monthly dashboard the works produce. The monthly analysis costs minutes and anticipates the deviations.
Note: the mechanics described correspond to private works under a unit-price contract; public works and fixed-price forms introduce their own certification and modification rules.