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Strategic Business Leader · Leading and managing projects

Project Success, Failure and Post-Completion Review in ACCA SBL

Updated 11 October 2026 · Fact-checked

A project succeeds when it delivers the agreed outcome on time, within budget and to quality, and also delivers the benefits and satisfies key stakeholders. It fails when it misses these. A post-completion review checks results against the plan after the project ends and records lessons for future projects.

Understand Project Success, Failure and Post-Completion Review

A project is a temporary effort with a defined start and end, set up to deliver a specific outcome. Because it is one-off, the organisation cannot rely on routine to get it right. That is why success and failure need careful thought.

Students often judge success only by the iron triangle: time, cost and quality (scope). A project can hit all three and still be a failure if the business case benefits never arrive. A project can also overrun and still be a success if the product is later hugely valuable. So you should separate project management success (was the project run well?) from project success (did the organisation gain what it wanted?).

Projects fail for recurring reasons. Common ones are unclear objectives, poor scope control (scope creep), weak business case, unrealistic estimates, lack of senior sponsorship, poor stakeholder engagement, weak risk management, inadequate resources or skills, poor communication, and weak governance and monitoring. Many failures start at initiation, long before the delivery team is in trouble.

A post-completion review (also called post-completion audit or post-implementation review) takes place after the project ends, and often again once benefits should have appeared. It compares actual results with the plan: time, cost, quality, benefits and stakeholder satisfaction. It asks why differences arose. Its main purpose is learning, not blame. Findings go into a lessons-learned record so the organisation improves its future projects.

For SBL, always tie your points to the scenario. Name the actual cause of failure in the case, say who is responsible, and suggest a practical action.

Key rules to remember

Iron triangle of project success
Success = delivered on time + within budget + to the required quality and scope
Necessary but not enough. Add benefits realised and stakeholder satisfaction for a full view.
Cost variance
Cost variance = budgeted cost − actual cost
A negative figure means an overspend. Use it in a review to quantify the gap against plan.
Schedule variance
Schedule variance (time) = planned duration − actual duration
A negative figure means a delay.
Benefits check
Benefits realised = actual benefits achieved vs benefits in the business case
Judged after completion, often months later. This separates project success from project management success.

How to solve Project Success, Failure and Post-Completion Review questions

Use this method for any SBL question on why a project failed, how to judge success, or how to run a review.

  1. 1Read the requirement and note the verb: identify, assess, explain, recommend or evaluate.
  2. 2Pick out the facts in the scenario: objectives, budget, deadlines, people, sponsor, stakeholders, and what went wrong.
  3. 3Define success or failure for this case. Use time, cost, quality, then benefits and stakeholders.
  4. 4Link each cause of failure to specific evidence in the scenario. Group causes, such as planning, people, governance and communication.
  5. 5Explain the consequence of each cause for the organisation or stakeholders.
  6. 6For a review question, set out what to review, who should do it, when, and how lessons will be recorded and used.
  7. 7Give practical recommendations with owners, and finish with a clear conclusion or judgement.
  8. 8Check that your answer is professional in tone and uses the case, to earn skills marks.

Quickest way: Cause-Evidence-Action in three lines

When to use it: When time is short and the question asks why a project failed or what to do about it.

  1. Write the success yardsticks in one line: time, cost, quality, benefits, stakeholders.
  2. For each point, write: cause, evidence from the case, consequence.
  3. Add one action per cause, such as a firmer scope control process, an active sponsor or a formal review.
  4. Close with a one-sentence judgement on whether the project failed and why.

Common mistakes in Project Success, Failure and Post-Completion Review

  • Defining success only as on time and on budget.

    The iron triangle is the most familiar idea.

    Fix: Add benefits realised and stakeholder satisfaction, and say a project can meet the triangle yet still fail.

  • Listing generic causes of failure with no link to the case.

    Students memorise lists and write them out.

    Fix: Quote the scenario fact behind every cause, then explain its effect.

  • Treating a post-completion review as a blame exercise.

    The word audit suggests finding fault.

    Fix: State that its purpose is learning and improvement, and that it should be open and constructive.

  • Ignoring the timing of the review.

    Students assume it happens only at handover.

    Fix: Say there can be an early review at completion and a later review when benefits should have appeared.

  • Forgetting that lessons must be used.

    Students stop at what the review finds.

    Fix: Explain how lessons are recorded, shared and built into future project planning and governance.

  • Blaming only the project manager.

    The manager is the obvious person in the story.

    Fix: Consider sponsor, board, business case, stakeholders and governance as sources of failure.

Worked examples

Example 1

A company launched a customer app. The budget was ₹2,00,00,000 and the deadline was 12 months. It was delivered in 15 months at a cost of ₹2,60,00,000. Requirements kept changing as the sales director added features, and no senior sponsor attended project meetings. After launch, few customers use the app. Assess whether the project was a success.

Show the solution
  1. Time: planned 12 months, actual 15 months. Schedule variance = 12 − 15 = −3 months, a 25% overrun (3 ÷ 12).
  2. Cost: budget ₹2,00,00,000, actual ₹2,60,00,000. Cost variance = 2,00,00,000 − 2,60,00,000 = −₹60,00,000, a 30% overspend (60 ÷ 200).
  3. Quality and scope: the repeated feature additions show scope creep, which caused the delay and cost overrun. There was no change control.
  4. Benefits: few customers use the app, so the business case benefits are not being achieved. Delivery alone did not create value.
  5. Stakeholders: the sales director drove changes, but customers do not use the product. The absence of a sponsor suggests weak governance and direction.
  6. Judgement: it failed on every measure.

Answer: The project failed. It overran time by 3 months (25%) and cost by ₹60,00,000 (30%), suffered scope creep without change control, lacked a sponsor, and did not achieve its customer adoption benefits.

Example 2

Six months after a new finance system went live, the board asks you to advise on a post-completion review. Explain what the review should cover and how it should be run.

Show the solution
  1. Purpose: compare results with the plan and business case, and learn lessons for future projects.
  2. Scope: time, cost and quality against plan, then benefits delivered against the business case, user satisfaction, and how well risks and changes were managed.
  3. Who: someone independent of the project team, such as internal audit or a manager from another area, so findings are objective. The project team and users should contribute.
  4. When: a review at handover, plus this one at six months when benefits should be visible.
  5. Method: interview users and sponsor, examine project records, and compare data such as processing times and errors with targets.
  6. Tone: focus on process and learning, not blame, so people speak openly.
  7. Output: a report with findings and recommendations, added to a lessons-learned record and used when planning new projects. The board should track actions.

Answer: The review should be independent and constructive. It should compare time, cost, quality and benefits with plan, find root causes of gaps, and feed lessons into future project planning, with the board following up actions.

Exam tips

  • Always bring in benefits and stakeholders when defining success. Markers look for more than the iron triangle.
  • Anchor every cause of failure to a fact in the case. Generic lists earn few marks.
  • In review questions, mention independence, timing, learning not blame, and how lessons are used.
  • Use short headed paragraphs and give a clear recommendation. This supports professional skills marks.
  • If figures are given, calculate the variances and percentages, then comment on what they mean.

Practice questions from Leading and managing projects

Project Success, Failure and Post-Completion Review in other exams

The same ground in other exams, if you are preparing for more than one or want another angle on it.

Project Success, Failure and Post-Completion Review: frequently asked questions

Why do projects fail in ACCA SBL?

Typical reasons are unclear objectives, scope creep, weak business case, poor estimates, no senior sponsor, weak stakeholder management, poor risk control and weak governance. In the exam, use only the causes that the case supports and show their effects.

What are project success criteria?

They are the measures agreed to judge the project. They normally include time, cost and quality, and should also include benefits realised and stakeholder satisfaction. Agree them at the start so everyone judges the project the same way.

What is a post-completion review?

It is a review after a project ends that compares actual results with the plan and business case. It finds out what went well and badly, and why. The aim is to record lessons for future projects.

Is a project that overruns always a failure?

No. If it delivers major benefits and stakeholders are satisfied, the overrun may be acceptable. Judge it against all the success criteria, not just time and cost.