Authored by WSP Fellow Kali Mercier, the report calls for a more consistent, evidence-led approach to infrastructure investment in Aotearoa New Zealand. It argues that stronger use of Cost Benefit Analysis (CBA) would help decision-makers better assess social, environmental and economic impacts, compare investment options more clearly, and deliver greater long-term value for New Zealanders.
Minister of Building and Construction Hon Chris Penk described the report as a tour de force, arguing that New Zealand needs a far more rigorous approach to cost‑benefit analysis in infrastructure investment. He stressed that the themes of capability, transparency and consistency should rise above partisanship, with political parties grounding their commitments in realism and evidence.
The Minister emphasised that cost benefit analysis must inform decisions early rather than justify choices already made, noting that real‑world policy-making is multifactorial. He also highlighted the tension between thorough analysis and opportunity cost, warning that endless evaluation can stall progress while delays themselves drive up project costs.
Labour spokesperson Arena Williams said infrastructure is one of the few areas of true political consensus in New Zealand, and that this matters as young people increasingly fear they’ll be worse off than their parents.
She said conversations about what government can do, supported by experts and democratic representation, are essential, and while cost‑benefit analysis is important, it isn’t the whole story. Infrastructure projects are investments for future generations, and the depth of the infrastructure deficit demands a shared long‑term approach. With construction inflation running at around 10 percent a year since the pandemic, she said delays now cost more than ever, making early starts, a stable pipeline and bipartisan planning critical for the future.
A panel discussion followed, featuring Kali, NZ Infrastructure Commission Te Waihanga director of infrastructure priorities and evaluation Nadine Dodge and Victoria University of Wellington professor Arthur Grimes.
The panel highlighted concerns about how infrastructure investment decisions are made, with Nadine noting that fewer than a quarter of projects have a cost‑benefit analysis completed before reaching Cabinet, making it difficult to hold decision‑makers to account.
Arthur argued that weak enforcement has eroded good practice, while misconceptions about cost‑benefit analysis persist - including forgetting that it's fundamentally a social tool, not just a fiscal one.
Both Nadine and Arthur stressed the need to communicate benefits in human terms and to show sensitivity to assumptions to build trust.
The panel agreed New Zealand has the tools to do better, with examples like insulation retrofits showing how CBA can sharpen choices, and that monetising what can be measured while acknowledging what cannot is essential. They supported the report’s call for earlier, sector‑level prioritisation.
More information about the report, including a downloadable copy, can be found here.
