AACE 57R-09 (Integrated Cost and Schedule Risk Analysis)

AACE 57R-09 is the AACE International Recommended Practice titled "Integrated Cost and Schedule Risk Analysis Using Risk Drivers and Monte Carlo Simulation of a CPM Model". Published in 2009 and based on methodology developed by John Hollmann, it is one of the most widely cited methodology references for QRA on major capital programmes — particularly UK infrastructure and defence work where integrated cost-schedule confidence (rather than separate QSRA + QCRA) is needed for gateway business cases.

The Risk Driver method that 57R-09 codifies is the practical innovation. A traditional Monte Carlo QRA treats activity durations and discrete risk events independently — each activity gets its own three-point estimate, each risk gets its own probability and impact. Risk Drivers model risks as factors that simultaneously affect multiple activities: a regulatory consenting risk affects every downstream construction activity in proportion; a labour-market risk affects every labour-intensive activity by a correlated factor; a weather risk affects all weather-sensitive activities together. This produces a more honest correlation structure than the default zero-correlation assumption that vanilla activity-by-activity QRA falls into, and a much more realistic upper-tail of the cost and schedule distributions.

The methodology requires: a deterministic CPM schedule with logic complete and float distributed; a discrete risk register with each risk characterised as a Risk Driver (probability of occurrence + impact range on the activities it affects); base-estimate uncertainty captured separately from discrete risks (so the model doesn't double-count where line items already have contingency baked in); explicit correlation between Risk Drivers where shared causes exist. The output is the joint cost-schedule probability distribution — a bivariate analogue of the QSRA-only and QCRA-only S-curves, with reference points at any (cost, date) pair.

57R-09 is the methodology UK programmes that need integrated cost-schedule confidence default to. It is the underlying reference for most major National Highways, Network Rail, Highways England (predecessor) and MoD CADMID-phase QRA work, and it is the methodology IPA reviewers expect to see cited in business cases where integrated cost-schedule confidence is presented. The competing AACE RP for similar work is 113R-20 (Integrated Cost and Schedule Risk Analysis and Contingency Determination Using Combined Parametric and Expected Value), which uses a different theoretical basis and is preferred where parametric cost estimating is the primary input. Both produce defensible integrated confidence positions; the choice between them depends on data availability and modelling preference.

Tool support for 57R-09 is good across the major QSRA platforms. Acumen Risk by Deltek implements the Risk Driver method natively. Safran Risk supports it via its risk register import and correlation specification. Primavera Risk Analysis (formerly Pertmaster, now on Oracle extended support) supports it through its risk register and correlation matrix. The method is independent of any specific tool — the methodology discipline (Risk Drivers characterised properly, correlation specified explicitly, base estimate uncertainty separated from discrete risks) matters far more than the platform choice.