Before the 5th edition arrived in 2017, the industry relied on the 2006 version. However, as international projects grew in complexity, the "rules of the game" needed an upgrade to ensure better transparency and risk management.
: These sections were separated for clearer implementation compared to previous editions.
| Model | Mechanism | Best For | Risk | | :--- | :--- | :--- | :--- | | | Fixed price for defined deliverables. | Well-defined, repetitive projects (e.g., standard warehouse). | Consultant bears all cost overrun risk. Employer loses transparency. | | B (Time-Based) | Hourly/daily rates + reimbursable expenses. | Feasibility studies, dispute resolution, ambiguous scope. | Employer bears unlimited cost risk; consultant has no efficiency incentive. | | C (Combined) | Lump sum for design + time-based for supervision. | Most infrastructure (e.g., bridge design fixed, site supervision hourly). | Balanced, but requires rigorous time tracking. | | D (Target Cost) | Shared savings/overrun on a target estimate. | Innovative or R&D-heavy projects. | Complex administration; requires mutual trust and open books. |