MOP Phases and Time Tracking: ESQ, APS, APD, PRO, EXE — How to Allocate Your Hours

The MOP law (Maitrise d'Ouvrage Publique -- Public Project Ownership) structures the entire project management mission into successive phases, each with its deliverables, requirements, and increasing level of detail. For an architect or engineering firm, this structure isn't just contractual: it's the best framework for organizing time tracking and ensuring the profitability of each project.

Yet in practice, few firms define an hour budget per phase from the outset. Time is tracked globally, alerts come too late, and overruns are often only discovered at the final billing stage.

This guide proposes a concrete approach: indicative allocation ratios by phase, early drift detection methods, and a complete case study to illustrate the process.

Overview of MOP Law Phases and Their Impact on Hours

Law No. 85-704 of July 12, 1985, known as the MOP law, and its implementing decrees define the core missions of the project manager. Each phase corresponds to a level of project progress, with identified deliverables and a contractually defined percentage of fees.

ESQ (Esquisse / Sketch): Exploratory phase. The architect translates the brief into spatial intentions, proposes architectural concepts, and verifies the project's feasibility. Documents are summary: site plans, conceptual diagrams, initial estimates.

APS (Avant-Projet Sommaire / Preliminary Design): The project takes shape. Plans are drawn at 1/200 scale, areas are validated, and the budget envelope is refined. This is the phase of intense dialogue with the project owner.

APD (Avant-Projet Definitif / Detailed Preliminary Design): The project is finalized in its dimensions, main materials, and construction principles. Plans move to 1/100 scale, cross-sections and facades are detailed. The cost estimate is established with a reduced margin of error.

PRO (Projet / Project): The most hour-intensive phase for graphic documents. Execution plans, construction details, CCTP (technical specifications) and DPGF (itemized cost breakdown) are produced. This is the foundation for contractor tendering.

EXE/DCE (Execution / Tender Documents): Preparation of tender documents, bid analysis, contract finalization. When the EXE mission is assigned to the project manager, execution plans and calculation notes are added.

DET (Direction de l'Execution des Travaux / Works Supervision): Site monitoring, compliance verification, variation management, payment certificate approval. A long phase, spanning the entire construction period.

AOR (Assistance aux Operations de Reception / Handover Assistance): Works acceptance, defect resolution, defects liability period. A phase often underestimated in terms of time.

Each phase consumes time very differently. Not budgeting by phase means flying blind.

Why structuring time tracking by phase is essential: the project management contract sets overall or per-phase fees. If time consumed during ESQ and APS exceeds the planned budget, it's the downstream phases (PRO, DET) that suffer, with a domino effect on deliverable quality and team workload. Structuring tracking by phase allows you to identify drifts while they're still correctable.

Indicative Time Allocation Ratios by MOP Phase

The ratios below are drawn from common practice in architecture firms and engineering offices. They don't constitute a standard, but a reference framework for building a realistic hour budget from the project's start.

Standard Allocation Ratios

These ratios total approximately 91% in average values. The remaining 9% covers general coordination, cross-cutting meetings, and project administration.

Variations by Project Type

Time allocation varies significantly depending on the type of project. A renovation project consumes proportionally more hours in upstream phases (surveys, assessments) and in site monitoring (contingencies). A public-access building (ERP) requires increased time in the PRO phase for safety and accessibility documentation.

How to use these ratios: as soon as the contract is signed, convert the fees into an overall hour budget (fees / team's weighted average hourly rate). Then apply the percentages per phase to obtain an hour budget per phase. This budget becomes your reference throughout the project.

For a project with EUR 200,000 in fees and an average rate of EUR 75/h, the overall budget is 2,667 hours. The APD (17%) represents 453 hours: that's your envelope for this phase.

How to Detect an Overrun from the Earliest Phases

Early detection of overruns is the primary benefit of time tracking structured by phase. Without this vigilance, drifts accumulate silently and only become visible at the end of the project, when it's too late to correct.

The Consumption Rate Method

The calculation is simple but remarkably effective:

Consumption rate = (hours consumed / budgeted hours) x 100

This rate must be compared against actual phase progress. A consumption rate of 60% is normal if the phase is 70% complete. It's a warning signal if the phase is only 40% complete.

Alert Thresholds to Implement

Three levels of vigilance allow you to react at the right time:

• Green threshold: consumption rate less than or equal to the progress rate. The project is on track.
• Amber threshold: consumption rate 10 to 20 points above the progress rate. Causes need to be analyzed and organization adjusted.
• Red threshold: 50% of the hour budget consumed before the midpoint of the phase. Overrun is virtually certain without immediate intervention.

The red threshold is the most critical signal: if half the budget is burned before mid-phase, the project will end up 30 to 50% over budget on that phase.

Why Upstream Phases Are the Most Dangerous

The ESQ and APS phases are the most exposed to overruns for several reasons:

1. Iterations are frequent: the project owner requests variants, brief adjustments, additional explorations. Each iteration consumes unplanned time.

2. The scope is fuzzy: at the project's start, the boundary between what falls within the mission and what requires additional studies is often poorly defined.

3. Tracking isn't yet in place: paradoxically, it's when the project is most vulnerable that time tracking is least rigorous.

4. The impact is disproportionate: a 20-hour overrun in ESQ (budget 140 h) represents 14% drift. The same overrun in DET (budget 700 h) represents only 3%.

The solution: implement time tracking from the very first day of the project, not after the APS phase. A tracking tool suited to project management professions enables you to automate this vigilance.

Organizing Your Tracking with Phase Milestones

Structuring by milestones transforms passive tracking (observing hours after the fact) into active management (making decisions at each phase transition).

One Milestone per MOP Phase

Each MOP phase naturally constitutes a project milestone. Each milestone corresponds to:

• A defined hour budget: calculated from ratios and adjusted to the project's specifics.
• Identified deliverables: the precise list of documents to produce to validate the phase.
• A target date: the contractual schedule sets deadlines for each phase.
• A responsible person: the project manager or project director who validates the transition to the next milestone.

Defining an Hour Budget per Milestone

The hour budget per milestone isn't limited to a single global figure. It should be broken down by resource type:

• Architect / project manager hours: coordination, design, client relations.
• Drafter / CAD technician hours: graphic production, BIM modeling.
• Structural / MEP / acoustics engineer hours (if integrated): technical studies.
• Administrative hours: document assembly, contract management.

This breakdown allows you to assign the right resources to the right phases and avoid bottlenecks. A senior architect spending 60% of their time on graphic production during the PRO phase isn't being used at the right level.

The Phase Review: The Moment of Truth

At each phase transition, a systematic review must answer three questions:

1. What is the hour balance of the phase that's ending? If the balance is negative (overrun), causes must be identified and subsequent phases adjusted.

2. Is the budget for subsequent phases still realistic? An overrun in APD may mean the project is more complex than anticipated. The PRO budget may need to be reevaluated.

3. Should we renegotiate with the project owner? If overruns are linked to out-of-scope requests or substantial modifications, a fee amendment is justified. The French Public Procurement Code (article R2194-5) provides for this possibility.

The phase review isn't an administrative formality. It's the moment when you decide whether to continue as is, adjust the team, or renegotiate the contract.

Case Study: A Collective Housing Project Tracked by Phase

Let's take a concrete example to illustrate the complete process, from initial budgeting to overrun detection and mid-project correction.

Project Data

• Brief: 35 collective housing units, R+4, underground parking.
• Construction cost: EUR 4,200,000 excl. tax.
• Project management fees: EUR 280,000 excl. tax (rate of 6.7%).
• Weighted average hourly rate: EUR 80/h.
• Overall hour budget: 280,000 / 80 = 3,500 hours.
• Estimated total duration: 30 months (6 months studies + 18 months construction + 6 months AOR).

Initial Allocation by Phase

Applying the ratios for a new-build housing project, the budget is allocated as follows:

Progress and Overrun Detection

ESQ phase: the sketch is completed in 125 hours out of the 140 budgeted. Positive balance of 15 hours. The phase review signals no alert.

APS phase: the preliminary design consumes 380 hours instead of 350. Overrun of 30 hours (+8.6%). The project owner requested two layout variants for the standard floor. The overrun is identified but considered acceptable. The cumulative balance shifts to -15 hours.

APD phase -- red alert: at mid-phase (4 weeks out of 8), tracking shows 370 hours consumed out of the 595 budgeted, i.e., a consumption rate of 62% for an estimated progress of 45%. The red threshold is breached.

Analysis reveals two causes:

1. Plan revision following the inspection office report: structural non-conformities require a modification of the structural grid, with repercussions on all floor plans.
2. Underestimation of underground parking complexity: the access ramp and ventilation require additional studies not included in the initial budget.

Corrective Actions Implemented

The project manager triggers three immediate actions:

1. APD team reinforcement: an additional drafter is assigned part-time to absorb the plan revisions. Cost: 80 additional hours allocated to APD.

2. PRO scope reduction: construction details for the parking are deferred to the EXE phase, reducing the PRO budget from 770 to 720 hours (-50 h).

3. Amendment request: since the modifications requested by the inspection office constitute a technical contingency, an amendment of EUR 15,000 (187 h) is negotiated with the project owner to cover the additional studies.

Project Outcome After Correction

Without phase-by-phase tracking, the APD overrun (+115 hours) wouldn't have been detected until the end of the project. It would have contaminated subsequent phases, and the overall overrun would probably have reached 300 to 400 hours (8 to 11%), or EUR 24,000 to 32,000 in lost margin.

Thanks to early detection and the three corrective actions, the overall overrun is contained at 85 hours (2.4%), of which 187 hours are covered by the amendment. The project ultimately delivers a margin above forecast.

Time tracking structured by MOP phase doesn't eliminate contingencies. It allows you to detect them in time, make informed decisions, and protect the project's overall profitability.

Structuring tracking by MOP phase is accessible to any firm, regardless of size. The key is to establish the framework from the project's start: an hour budget per phase, defined alert thresholds, and a systematic review at each transition. The ratios proposed in this article are a starting point; each firm should refine them based on its own history and project types.

For architecture firms looking to industrialize this approach, a time tracking tool with milestone breakdown and automatic alerts radically transforms management capability. The investment in entry time is minimal; the return in visibility and profitability is considerable.