Plain definition
A post-investment review compares an approved investment case with actual results after implementation. It asks whether the project delivered the cash, benefits, timing, risks, and operating changes that justified approval, and why material differences occurred. Its purpose is to improve future decisions and execution, not to punish a forecast for being uncertain.
The review must use the original decision boundary. If the original case excluded a benefit or cost, adding it only after the result is known can make a poor comparison look good. Separate a forecasting error from an execution choice, an external shock, and a change management deliberately approved later.
Illustrative example
Monetary examples use Saudi riyals (SAR). The same principles apply in other currencies.
Suppose a system was approved to reduce monthly rework by within six months. After six months, measured reduction is and implementation cost is higher than planned because training took longer. The review checks the baseline, adoption rate, work actually removed, cash timing, and owner actions—not only the final variance.
Management may discover that the technology works but users bypass it, or that the benefit is real but arrives later. Those are different lessons and lead to different actions on the current project and the next business case.
A review should be scheduled at approval, with a named owner and measures that can be observed.
Why it matters
Without feedback, organisations repeat the same optimism about demand, timing, working capital, or delivery capacity. A disciplined review builds an evidence base for better assumptions.
Practical consequence
At approval, preserve the case, key assumptions, decision rule, expected milestones, and baseline measures. Choose review dates that match when benefits can realistically appear. Reconcile actual cash and operating evidence to the original case, explain material variances with owners and actions, and feed the lesson into future hurdle rates, estimates, and approval gates.