Construction cost studies in France: the economist's role, stages and deliverables

The construction economist is a building professional specialised in the assessment, control and optimisation of a project's costs. They sit within the design team, alongside the architect, the structural engineer, the energy consultant and the other technical contributors. The role cuts across all of them: the economist turns architectural intentions into figures, watches for budget drift and makes sure the project stays financially viable at every step of its design and construction.

Contrary to a common assumption, the economist is not there to shrink the ambitions of the project. They are there to make them affordable. A good economist does not say "that costs too much", they say "here are the trade-offs needed to stay within the budget, and here are the savings available without degrading quality".

In France, the construction economist typically holds a two-year higher technician diploma in construction economics, a university degree in civil engineering or a specialised vocational degree. They may practise as an employee of a design practice, as a freelance, or within a dedicated structure such as Quostra. The profession has no compulsory governing body, but practitioners may join UNTEC, the national union of construction economists, which publishes competence frameworks and indicative fee scales.

Under a full design appointment, the economist is an unavoidable figure. They come in at the first sketches to set a budget band, then refine their assessments progressively as the stages advance. Their work continuously feeds the decisions of the architect and the client: can this material, this structural type, this level of specification be maintained and still stay within the budget?

ℹ Worth knowing On public projects, an economist within the design team is often required at the pre-qualification stage. On private projects, one is strongly advised as soon as the works exceed 300,000 € excluding VAT.

The economist accompanies the project across its whole life, from the concept stage to practical completion. The nature and precision of the work vary with the stage, but the objective never changes: to keep design choices and the client's financial constraints consistent with each other.

At this point the drawings are still very undeveloped. The economist works from ratios per square metre of floor area, sector cost data and their knowledge of the local market. They produce a budget band that lets the client confirm the economic feasibility of the project before committing to fuller studies. The expected precision is of the order of 20 to 30 %.

The drawings are more advanced. The economist can now measure the principal trades — structure, roof, façades, technical packages — and set out detailed pricing by package. Precision improves to 10 to 15 %. It is often at this stage that the architect and the client take the most structuring trade-off decisions.

Production information is under way. The economist writes the particular technical specification for each package and establishes the definitive quantity schedules. These documents become the basis for the tender package.

The economist finalises every financial document in the package: the pricing schedule for lump-sum contracts, the priced bill of estimated quantities, the particular administrative conditions and the tender rules. Together they let contractors price their offer on comparable terms.

When the tenders come in, the economist analyses and compares the contractors' proposals, detects any abnormally low offer and writes a summary report for the client. They support the negotiation and prepare the works contracts.

During the works the economist follows the movement of costs: they check the interim valuations submitted by the contractors, manage variations, anticipate overruns and draw up the final account at practical completion.

What the economist produces can be grouped into five thematic families, each corresponding to a key step of the project.

These are the first documents produced. They range from the simple outline-stage band to the detailed developed-design estimate. Their purpose is to give the client a reliable view of the budget to be raised, and the architect a reference frame for their technical choices. Precision improves with the stages: from 30 % at concept to 10 % at developed design.

→ Related articles in this cocoon: the outline-stage estimate, developed-design quantities, the reliability of a concept-stage estimate, construction cost ratios.

The particular technical specification and the quantity schedules are the most time-consuming documents to produce. They define precisely what is expected of each contractor and form the contractual basis of the works packages. An error or an omission in these documents can generate costly disputes.

→ Related articles: the tender package, the technical specification by package, pricing schedule versus priced bill.

At the close of the tender period, the economist compares the proposals, detects anomalies, ranks the offers and puts a reasoned recommendation to the client. The work is technical and legal at once.

→ Related articles: tender analysis at the award stage, how to detect an abnormally low tender, the tender analysis report.

Once the contracts are signed, the economist follows the financial execution of the project: approving interim valuations, managing variations, drafting contract amendments, maintaining a budget dashboard. Finally they produce the final account that definitively settles the position between client and each contractor.

→ Related articles: cost control on site, the final account, my project is over budget — what now?

Outside the classic design cycle, the economist may be appointed for one-off studies: an economic feasibility study, an audit of a project that is drifting, a value study weighing cost against performance, or a comparative analysis of construction variants. These call for analytical and synthetic skills beyond the mere production of prices.

ℹ Quostra's deliverables Quostra produces all of these deliverables on demand, with no minimum term. Each assignment goes to an experienced economist, with a delivery time calculated automatically when the project is submitted. Indicative lead time: 72 working hours for an outline-stage estimate or a developed-design measure on an ordinary residential project.

The question is less "do we need an economist?" than "at what point does bringing one in pay for itself?". The answer is almost always: as early as possible.

An outline-stage estimate carried out upstream avoids the most frequent scenario on badly steered projects: reaching the tender stage with pricing 30 % above the budget the client signed off, and having to redo part of the design work. The cost of an outline estimate bears no comparison with the cost of the redesign it prevents.

A poorly written specification, incomplete schedules, or inconsistencies between the written documents and the drawings are direct sources of extra cost on site. Contractors price uncertainty, and bill the unforeseen as variations. A solid tender package is the best investment available for controlling construction costs.

Many clients discover they have exceeded their budget only at practical completion. Regular cost monitoring, even in a light form, allows drift to be anticipated and acted on before it becomes irreversible.

• New-build projects above 200,000 € excluding VAT: the economist is indispensable from the outline stage.
• Refurbishment: more unknowns, less reliable ratios, and therefore an even more valuable economist.
• Public projects: an economist is often required by the tender rules.
• Small projects below 100,000 € excluding VAT: an outline estimate alone may be enough to frame the budget.

Quostra is a construction economics service on demand. It addresses architects, design-team project managers and clients who need precise cost deliverables without wanting, or being able, to carry a full-time economist in their team.

The model is simple: you submit your project on quostra.com with the documents available — drawings, brief, programme. Quostra calculates the delivery time automatically and puts you in contact with a qualified economist who produces the deliverable requested. You receive a finished document, ready to use.

Quostra covers the whole design cycle:

• Outline and developed-design estimates
• Complete tender packages: specification, pricing schedule, priced bill, contract conditions
• Tender analysis and award reports
• Cost control on site and the final account
• One-off studies: feasibility, audit, optimisation

You have better things to do. Submit your project on quostra.com and an economist takes over within 72 working hours.

The construction economist is the guarantor of a project's economic coherence throughout its life. They produce five families of deliverables — estimates, tender documents, tender analysis, cost control on site, specialist studies — each matching a key stage of the project. Their value is greatest when they are brought in early, ahead of the detailed studies, and maintain continuity of monitoring through to completion.

This cocoon explores each of these families in turn, to explain what they contain, how they are produced and what part they play in controlling the cost of your project.