What Is an Integrated Baseline Review? IBR Process Explained

<div class="ge-article-wrapper"><nav class="ge-toc" aria-label="Table of contents"><p class="ge-toc-label">In this article</p><ul class="ge-toc-list"><li><a href="#why-ibr-exists">Why IBR Exists</a></li><li><a href="#the-ibr-process">The IBR Process</a></li><li><a href="#what-ibr-actually-examines">What IBR Actually Examines</a></li><li><a href="#worked-example-ibr-on-an-80m-government-infrastructure-project">Worked Example: IBR on an £80M Government Infrastructure Project</a></li><li><a href="#ibr-in-uk-construction-vs-us-defence">IBR in UK Construction vs US Defence</a></li><li><a href="#common-mistakes">Common Mistakes</a></li><li><a href="#frequently-asked-questions">Frequently Asked Questions</a></li></ul></nav><article class="ge-article-body"><p>An Integrated Baseline Review (IBR) is a joint assessment between the client (typically a government body) and the contractor to verify that the performance measurement baseline (PMB) is realistic, achievable, and properly structured. It happens once, usually 90 to 180 days after Authority to Proceed (ATP), and its purpose is brutally simple: can you actually deliver what you've promised, for the price you've quoted, in the time you've committed to?</p><p>If not, better to find out now than at month 18 when the <a href="/en/earned-value/definitions/cost-performance-index">CPI</a> is sitting at 0.72 and everyone's pointing fingers.</p><p>IBR is part of the <a href="/en/earned-value/definitions">earned value definitions glossary</a>. For the broader context of how the PMB feeds <a href="/en/earned-value">earned value management</a>, see the pillar guide.</p><h2 id="why-ibr-exists">Why IBR Exists</h2><p>The short answer: because contractors are optimistic and clients are trusting.</p><p>The longer answer: on government contracts above certain thresholds (typically £50M+ on MOD projects, though this varies by department), the client needs confidence that the contractor's <a href="/en/earned-value/implementation-guide">EVM system</a> will produce meaningful data. A pretty-looking <a href="/en/earned-value/s-curve-tracking">S-curve</a> means nothing if the baseline behind it is fiction. IBR is the stress test.</p><p>Before EIA 748 (the US standard adopted by many UK government bodies), contractors would set up baselines that looked perfect on paper. Then reality hit, the baseline became irrelevant within six months, and the earned value reports told you nothing except how far behind you were relative to a fantasy. IBR exists to prevent that.</p><p>On one MOD infrastructure programme I worked adjacent to, the IBR uncovered that 23% of the baseline activities had no resource loading. The contractor had time-phased the budget beautifully but hadn't checked whether they could actually get the labour and plant to site when the programme said they needed it. The IBR team flagged it. The baseline was reworked. The project still had problems, but at least the EVM data was measuring something real.</p><h2 id="the-ibr-process">The IBR Process</h2><pre class="ge-ascii-diagram ge-anim"> IBR PROCESS FLOW ================= CONTRACT AWARD │ v ┌──────────────────────────┐ │ AUTHORITY TO PROCEED │ Day 0 │ (ATP) │ └──────────┬───────────────┘ │ │ 60-90 days: Contractor sets up PMB │ - Cost-loads the programme │ - Establishes control accounts │ - Assigns responsible managers │ v ┌──────────────────────────┐ │ PRE-IBR PREPARATION │ Day 60-90 │ │ │ Contractor submits: │ │ - WBS dictionary │ │ - RAM (Responsibility │ │ Assignment Matrix) │ │ - Cost-loaded programme │ │ - Risk register │ │ - Management Reserve │ │ log │ └──────────┬───────────────┘ │ │ 2-4 weeks: Client team reviews documents │ v ┌──────────────────────────┐ │ IBR CONDUCT (ON-SITE) │ Day 90-120 │ │ │ Duration: 3-5 days │ │ │ │ Day 1: Opening brief, │ │ overview of PMB │ │ Day 2-3: Control account│ │ deep dives │ │ Day 4: Cross-cutting │ │ issues, risk │ │ review │ │ Day 5: Out-brief with │ │ findings │ └──────────┬───────────────┘ │ │ Findings rated: │ - Satisfactory │ - Corrective Action Required (CAR) │ - Observation (minor) │ v ┌──────────────────────────┐ │ POST-IBR RESOLUTION │ Day 120-180 │ │ │ Contractor addresses │ │ CARs within agreed │ │ timeframe (30-60 days) │ │ │ │ Client verifies fixes │ └──────────┬───────────────┘ │ v ┌──────────────────────────┐ │ BASELINE ACCEPTED │ Day 150-180 │ │ │ PMB is now the official │ │ measurement reference │ │ for all EVM reporting │ └──────────────────────────┘ </pre><h2 id="what-ibr-actually-examines">What IBR Actually Examines</h2><p>IBR isn't a tick-box exercise. The review team, typically 4 to 8 people from the client organisation, including a cost analyst, scheduler, and subject matter experts, examines five areas:</p><p><strong>1. Planning and scheduling.</strong> Is the programme logic-linked? Are durations reasonable? Do critical path activities have float, or is the schedule built on zero contingency? Can the contractor explain the sequencing, or did a planner build it in isolation?</p><p><strong>2. Resource allocation.</strong> Do the labour and plant resources match the programme requirements? If the baseline says 40 operatives on site by month 6, can the contractor demonstrate where they're coming from? On specialist trades (rail signalling, high-voltage electrical), this is often where the first cracks appear.</p><p><strong>3. Budget phasing.</strong> Does the cost profile match the programme? A flat cost profile on a project with a ramp-up and wind-down is suspicious. The S-curve should align with the works sequence, not look like a straight line someone drew in Excel.</p><p><strong>4. Risk and opportunity.</strong> Has the contractor identified realistic risks and priced them into management reserve? Is the management reserve proportionate, too much means the baseline is padded, too little means the first problem will blow the budget.</p><p><strong>5. Control account structure.</strong> Is every pound of budget assigned to a control account? Does every control account have a responsible manager? Can that manager explain their scope, schedule, and budget, or are they reading from a brief the commercial team wrote the night before?</p><h2 id="worked-example-ibr-on-an-80m-government-infrastructure-project">Worked Example: IBR on an £80M Government Infrastructure Project</h2><span class="ge-worked-label">Worked Example</span><div class="ge-callout ge-anim"><p><strong>Scenario:</strong> An £80M MOD facilities upgrade programme in Wiltshire, procured under a target cost contract with EVM requirements. ATP is granted on 3 February 2025. IBR is scheduled for 12-16 May 2025 (98 days post-ATP).</p><p><strong>Pre-IBR submission (received 14 April 2025):</strong></p><ul><li>WBS: 5 levels, 420 work packages</li><li>Control accounts: 38, each with a named Control Account Manager (CAM)</li><li><a href="/en/earned-value/definitions/budget-at-completion">BAC</a>: £80,000,000</li><li>Management Reserve: £4,200,000 (5.25% of BAC)</li><li>Programme: 580 activities, logic-linked, cost-loaded</li><li>Risk register: 64 identified risks, 22 priced into management reserve</li></ul><p><strong>IBR findings (16 May 2025 out-brief):</strong></p><div class="ge-table-wrap ge-anim"><table class="ge-table"><thead><tr><th>Finding</th><th>Category</th><th>Detail</th><th>Rating</th></tr></thead><tbody><tr><td>F-01</td><td>Scheduling</td><td>14 activities on critical path have zero float. No acceleration options identified.</td><td>CAR</td></tr><tr><td>F-02</td><td>Resources</td><td>M&amp;E work package (£18M) relies on a single specialist subcontractor. No backup identified.</td><td>CAR</td></tr><tr><td>F-03</td><td>Budget</td><td>Control Account 14 (temporary works, £3.2M) has 40% of budget allocated to month 1, remaining 60% spread evenly. Cost profile doesn't match programme logic.</td><td>CAR</td></tr><tr><td>F-04</td><td>Risk</td><td>Management reserve of 5.25% is at the low end for a project of this complexity. Industry benchmark for similar MOD projects is 7-10%.</td><td>Observation</td></tr><tr><td>F-05</td><td>Controls</td><td>CAM for Control Account 22 couldn't explain the relationship between their budget phasing and the programme activities.</td><td>CAR</td></tr><tr><td>F-06</td><td>Risk</td><td>Three high-impact risks (ground contamination, planning consent delay, material price escalation) identified but not priced into management reserve.</td><td>CAR</td></tr></tbody></table></div><p><strong>Outcome:</strong> 5 CARs, 1 observation. The contractor has 45 days to resolve CARs and resubmit. The project cannot report formal EVM metrics until the baseline is accepted.</p><p><strong>Resolution (30 June 2025):</strong></p><ul><li>F-01: Re-sequenced critical path, introduced 5 days float on 8 of the 14 activities</li><li>F-02: Identified and pre-qualified a second M&amp;E subcontractor</li><li>F-03: Re-phased CA-14 budget to match programme logic</li><li>F-05: Replaced CAM with the package QS who understood the detail</li><li>F-06: Priced three risks into management reserve (MR now £5,800,000 = 7.25% of BAC)</li></ul><p>Baseline accepted on 4 July 2025. First formal EVM report: August 2025 (month 6).</p></div><h2 id="ibr-in-uk-construction-vs-us-defence">IBR in UK Construction vs US Defence</h2><p>Most IBR literature comes from the US Department of Defense, where it's been standard practice since the 1990s. In UK construction, IBR is far less common but growing, particularly on Network Rail, MOD, and nuclear decommissioning programmes.</p><p>The key differences:</p><div class="ge-table-wrap ge-anim"><table class="ge-table"><thead><tr><th>Aspect</th><th>US DoD</th><th>UK Government Construction</th></tr></thead><tbody><tr><td>Mandate</td><td>Required above $20M ACAT threshold</td><td>Varies by department, MOD uses it most</td></tr><tr><td>Standard</td><td>EIA-748-D</td><td>Often references EIA-748 or BS 6079</td></tr><tr><td>Timing</td><td>180 days post-ATP (hard deadline)</td><td>Typically 90-180 days (flexible)</td></tr><tr><td>Team size</td><td>8-15 reviewers</td><td>4-8 reviewers</td></tr><tr><td>Enforcement</td><td>Formal Corrective Action process</td><td>Usually collaborative resolution</td></tr></tbody></table></div><p>On commercial NEC4 contracts, there's no contractual requirement for IBR. But I'd argue the Accepted Programme process under clauses 31 and 32 serves a similar function, the Project Manager is reviewing whether the programme (and by extension, the baseline) is realistic before accepting it. The rigour isn't the same, but the principle is.</p><h2 id="common-mistakes">Common Mistakes</h2><p><strong>Treating IBR as an audit.</strong> It's not. It's a collaborative review. The best IBRs I've seen involved the client team and contractor team sitting side by side, working through control accounts together. The worst involved a room full of people defending documents they'd prepared the night before.</p><p><strong>Scheduling IBR too late.</strong> If you run IBR at month 8 of a 24-month project, you've already got six months of EVM data based on a baseline nobody's verified. Any problems found now require retrospective correction. Run it early, 90 days post-ATP is the sweet spot.</p><p><strong>Not involving Control Account Managers.</strong> If the CAMs aren't in the room during IBR, the review is hollow. The whole point is testing whether the people responsible for delivering the work understand and own their baseline. A senior commercial manager presenting on behalf of a CAM is a red flag.</p><p><strong>Ignoring IBR findings post-review.</strong> CARs have resolution deadlines for a reason. I've seen projects where CARs were "acknowledged" and then quietly forgotten. Six months later, the exact problem the IBR identified materialises, and suddenly everyone remembers the finding that was never addressed.</p><div class="ge-product-note ge-anim"><p><strong>How Gather helps.</strong> Gather's AI reads your site diaries daily and maps progress against your cost-loaded programme, giving you accurate earned value data without manual spreadsheet updates. <a href="https://gatherinsights.com/contact">Book a demo</a> to see it working on a live NEC4 project.</p></div><h2 id="frequently-asked-questions">Frequently Asked Questions</h2><h3>Is IBR mandatory on all UK government contracts?</h3><p>No. It depends on the department and the contract value. MOD contracts above certain thresholds typically require it. Network Rail and Highways England have their own EVM requirements that may or may not include formal IBR. If the contract specification references EIA-748 or ANSI/EIA-748, expect an IBR.</p><h3>How long does an IBR take?</h3><p>The on-site review itself is typically 3 to 5 days. But preparation takes 4 to 8 weeks (assembling documentation, pre-briefing the review team) and resolution of CARs takes another 4 to 8 weeks. End to end, budget 3 to 4 months from starting preparation to baseline acceptance.</p><h3>What happens if the baseline fails IBR?</h3><p>The contractor addresses the Corrective Action Required findings and resubmits. There's no "fail" in the pass/fail sense. It's iterative. But a baseline with more than 5-6 CARs raises serious questions about the contractor's EVM capability. In extreme cases, the client may bring in an independent EVM consultant to help rebuild the baseline.</p><h3>Can IBR be repeated during the project?</h3><p>Formally, IBR is a one-time event. But if the project undergoes a major re-baseline (more than 10% BAC change, for instance), a follow-up baseline review, sometimes called an over-target baseline (OTB) review, may be conducted. It follows a similar process but focuses specifically on the changes from the original baseline.</p></article></div>