New Zealand children in homes fitted with heating and insulation were 30% less likely to be hospitalised

The 30% and the 2,800 measure different things. The 30% is a risk: how likely a child in the programme was to be admitted at all in the five years after the home was improved ^[1]. The 2,800 is a count of admissions, set against the researchers' model of what would have happened otherwise ^[2]. The analysis covered more than 17,000 children aged 2 to 18, from families enrolled between 2014 and 2023 ^[3]. Across that cohort, 2,800 averted admissions comes to roughly 0.16 per child, or about one for every six children enrolled ^[14].

The thing this doesn't tell you is how "otherwise" was built. The paper's title describes a large cohort of low-income families ^[7], but the release does not say who the enrolled children were compared with. That choice matters here. Families qualify because their children are in low-income households and at risk of housing-related illness ^[4]. Any service that enrolls people at a moment of need can see admissions fall afterwards for reasons unrelated to what it delivered. Comparing them with similar children who had not yet enrolled, or with the same children before enrolment, would rule much of that out. Until the design is visible, I'd treat the 30% as the gap observed in this cohort. How much of it the repairs caused has not been shown yet.

The illnesses involved do not fall evenly. Māori and Pacific children are particularly at risk of pneumonia, chest infections, rheumatic fever and skin infections, according to lead researcher Ellie Johnson, a research fellow in Otago's Department of Public Health ^[9]. "Each year, 82,000 people are hospitalized and 230 people die from conditions associated with housing, including exposure to dampness, mold, cold and overcrowding," Johnson said of the toll across all ages ^[10].

The claim that the spending pays for itself comes from an earlier study. The university prepared a five-year evaluation of the scheme in partnership with Health NZ, published in 2024 ^[11]. Health NZ is also the partner on the new analysis ^[6]. So both results come from the same evaluators, working with the agency whose spending they assess.

Johnson ties the results to how the scheme is run and paid for. "Community-led interventions such as the Healthy Homes Initiative can have a significant impact on health outcomes and contribute to the wider public good when they are given sustained government and philanthropic support," she said ^[12]. She also said that while the scheme is a good way to improve the housing stock, the government needs to raise the share of publicly funded, affordable public and community housing. She said that share is low compared with other OECD countries ^[13].