Major projects are often promoted using large figures for investment, jobs and GDP. These numbers may describe economic activity, but they do not necessarily demonstrate that the project creates net economic value.
Gross activity is not automatically additional
Construction spending, employment and supply-chain purchases may be visible and significant. However, resources used by the project have opportunity costs. Workers, capital, land and public funds could have been used elsewhere.
A credible assessment therefore needs a counterfactual: what would happen without the project? Only activity attributable to the project should be described as additional impact.
Net benefit requires a broader ledger
Social cost-benefit analysis considers benefits and costs across society. These may include consumer benefits, productivity, environmental effects, travel-time savings, externalities, public-service costs and distributional impacts.
Transfers—such as some taxes, subsidies or payments between domestic parties—must also be distinguished from genuine resource costs and benefits.
Why the distinction matters
An investment can produce substantial gross activity while offering modest net benefit. Conversely, a relatively small project may create high net value through productivity, accessibility or avoided costs.
The practical implication is simple: decision-makers should not rely on impact figures alone. A strong business case makes activity, attributable impact and net economic benefit separately visible.