A comprehensive overview of AACE International's peer-reviewed Recommended Practices (RPs) that establish the technical standards for cost estimating, risk analysis, planning and scheduling, and earned value management.
AACE International Recommended Practices (RPs) are peer-reviewed technical documents that provide standardized guidelines, methodologies, and best practices for cost engineering, project controls, and total cost management. Developed by volunteer committees of experienced practitioners, these documents represent the collective expertise of the global cost engineering profession.
With over 120 published Recommended Practices, AACE's RP library covers virtually every aspect of project cost management - from initial estimate classification and contingency determination through to forensic schedule analysis and claims resolution. Each RP undergoes rigorous technical review before publication and is periodically updated to reflect advances in industry practice.
AACE RPs form the technical backbone of the Total Cost Management (TCM) Framework, which is AACE's integrated process for managing all aspects of project and program cost throughout the asset lifecycle. RPs are organized within the TCM Framework's process map, providing detailed guidance for each process area. They are also a primary reference for AACE's professional certification examinations including the CCP, CEP, PSP, and EVP.
AACE Recommended Practices are organized across several major project controls disciplines. Below are the most significant RPs within each category, referenced extensively in industry practice and certification examinations.
These RPs define how cost estimates should be classified, structured, and prepared across different industries and project phases.
The risk analysis RP series provides a comprehensive framework for quantitative risk assessment and contingency determination on capital projects.
These RPs address the planning, development, analysis, and forensic examination of project schedules for construction and engineering projects.
The earned value series provides practical guidance for implementing and interpreting EVM on capital projects and programs.
10S-90: Cost Engineering Terminology (revised July 2025) is AACE's standard glossary defining over 3,000 terms used across all cost engineering disciplines. It serves as the foundational reference for all other Recommended Practices and is freely available from the AACE website. The "S" designation indicates it is a "Standard" rather than a "Recommended Practice," reflecting its authoritative status within AACE's publications.
These five Recommended Practices are among the most widely referenced standards in the cost engineering profession and are essential knowledge for practitioners working on capital projects.
The most widely referenced estimate classification standard in the world, 18R-97 maps five estimate classes to project maturity levels for engineering, procurement, and construction (EPC) projects in process industries.
Key Contributions:
Why It Matters: This RP is the global standard for communicating estimate reliability and has been adapted by numerous industry-specific versions. Queensland's PCEM estimate classification system aligns closely with the principles established in this standard.
This foundational RP establishes the general principles for estimating contingency on capital projects using quantitative risk analysis (QRA) methods rather than arbitrary percentage additions.
Key Contributions:
Why It Matters: By establishing that contingency should be determined through systematic risk analysis rather than arbitrary allowances, this RP fundamentally changed how the industry approaches cost risk management. The P50 and P90 confidence levels used in Australian infrastructure practice are grounded in these principles.
The definitive reference for delay analysis methodologies, 29R-03 provides a taxonomy and framework for conducting forensic schedule analysis in construction disputes and claims.
Key Contributions:
Why It Matters: This RP is the most widely cited reference in international construction dispute resolution. It provides an objective framework that courts, arbitrators, and expert witnesses rely upon when evaluating delay claims on infrastructure projects.
The parent standard for all industry-specific estimate classification RPs, 17R-97 establishes the general principles and generic classification matrix that maps estimate classes to project scope definition maturity.
Key Contributions:
Why It Matters: As the foundational estimate classification standard, 17R-97 provides the common language that project stakeholders use to communicate estimate maturity and reliability. The RP was editorially revised in February 2025, demonstrating ongoing commitment to keeping the standard current.
This RP provides comprehensive guidance on developing resource-loaded, logic-driven project schedules using the Critical Path Method (CPM) and establishes the standards for professional scheduling practice.
Key Contributions:
Why It Matters: Effective scheduling underpins successful project delivery. RP 37R-06 provides the technical standard against which project schedules are assessed for quality and completeness, making it essential for both schedule development and independent schedule reviews on infrastructure projects.
AACE Recommended Practices are available through several channels, with pricing that varies based on membership status and format.
Individual RPs are available for purchase in digital format through AACE International's online bookstore. AACE members receive discounted pricing on all publications. Bundled collections organized by discipline area are also available at reduced per-document pricing.
AACE membership provides access to select Recommended Practices as part of the membership package, along with discounted pricing on all publications. The membership also includes access to the AACE Technical Library, which contains technical papers, presentations, and supplementary reference materials.
Table of contents and summary descriptions for all RPs are freely available on the AACE website. Additionally, selected foundational documents such as 10S-90 (Cost Engineering Terminology) can be downloaded at no cost. These free resources are valuable for understanding the scope and applicability of each RP before purchasing.
At Cenex, we integrate AACE Recommended Practices into our project delivery methodology to ensure our cost engineering services meet the highest international standards.
We classify all cost estimates in accordance with AACE 17R-97 and its industry-specific derivatives, ensuring stakeholders clearly understand the maturity, basis, and expected accuracy of each estimate we deliver. This aligns with PCEM requirements for Queensland infrastructure projects.
Our risk modelling methodology follows the principles established in the 40R-08 series. We use Monte Carlo simulation and systematic risk identification to determine contingency provisions at P50 and P90 confidence levels, replacing arbitrary percentage allowances with defensible, risk-based assessments.
When engaged on delay claims and dispute resolution, our scheduling professionals apply the methodologies defined in RP 29R-03 (Forensic Schedule Analysis) and RP 37R-06 (Schedule Development) to deliver defensible, internationally recognized analysis that stands up to independent scrutiny.
Our team maintains current knowledge of AACE standards through active AACE membership, conference participation, and ongoing professional development. We ensure our practices reflect the latest revisions and updates to the RP library, keeping our methodologies at the forefront of the profession.
AACE Recommended Practices (RPs) are peer-reviewed technical documents published by AACE International that provide standardized guidelines and methodologies for cost engineering, project controls, and total cost management. With over 120 published RPs, they represent the collective knowledge and best practices of the cost engineering profession and serve as the technical backbone of the TCM Framework.
RP 18R-97 (Cost Estimate Classification System as Applied in Engineering, Procurement, and Construction for the Process Industries) is one of the most widely referenced AACE RPs globally. It provides the definitive five-class estimate classification system that maps estimate accuracy ranges to project maturity levels. Its parent standard, 17R-97, provides the generic classification framework used across all industries.
AACE RP 17R-97 establishes the general framework for cost estimate classification, defining five estimate classes (Class 5 through Class 1) based on project definition maturity. Industry-specific RPs like 18R-97 (process industries), 56R-08 (building and general construction), and 98R-18 (mining and mineral processing) apply these principles to specific sectors with tailored maturity matrices and accuracy expectations.
Most AACE Recommended Practices are available for purchase through the AACE International online bookstore, with members receiving discounted pricing. Some RPs, such as 10S-90 (Cost Engineering Terminology), are available as free downloads from the AACE website. Table of contents and summaries for all RPs are publicly accessible, allowing practitioners to evaluate relevance before purchasing.
AACE RPs are updated periodically through a formal peer review process managed by volunteer technical committees. Updates incorporate new industry practices, lessons learned, and stakeholder feedback. The frequency of updates varies by document - some undergo major revisions every few years while others receive editorial updates more frequently. For example, 10S-90 was revised in July 2025, and 17R-97 was editorially revised in February 2025.
The most relevant AACE RPs for Australian infrastructure include 17R-97 and 56R-08 (estimate classification), 40R-08 and 44R-08 (contingency and risk analysis), 29R-03 (forensic schedule analysis), and the 81R/82R/86R series (earned value management). These standards are widely referenced in Australian cost engineering practice alongside local frameworks such as Queensland's Project Cost Estimating Manual (PCEM).
Cenex delivers cost estimates, risk analysis, and project controls services grounded in AACE Recommended Practices and aligned with Australian infrastructure standards.