Evidence asymmetry in Australian public spending: why health alone cannot bear a higher burden of proof.

Australian Commonwealth portfolio expenditure operates under structurally asymmetric evidentiary standards that disproportionately burden the Health portfolio and distort cross-portfolio funding decisions. Despite comparable fiscal scale, Health (AU$70.8 billion projected for 2025-26) is subject to rigorous formal evaluation through mechanisms such as the Pharmaceutical Benefits Advisory Committee and Medical Services Advisory Committee, while portfolios including Education (AU$72.5 billion) and Defence (AU$83.2 billion) justify expenditure predominantly through strategic alignment, narrative reporting, and performance indicators without reference to validated methodological benchmarks. This creates a paradox in which Health face greater barriers to funding than those relying on informal justificatory approaches, limiting the ability of central agencies to make transparent, comparable, and welfare-maximising funding decisions. Drawing on cross-portfolio analysis of Commonwealth Budget papers, portfolio budget statements, and central agency guidance documents, this commentary demonstrates that this asymmetry is structural rather than incidental, arising from inconsistently applied evaluative expectations that undermine efficient allocation of public resources. The Federal Government's Measuring What Matters framework explicitly endorses broader conceptions of value including wellbeing and equity, yet these remain absent from Expenditure Review Committee funding decisions, widening the gap between stated policy priorities and practice. Social Return on Investment is proposed as one potential pragmatic bridging framework capable of extending proportional evaluative standards across portfolios currently assessed through informal mechanisms, complementing established health economic methods. Aligning evidentiary standards with expenditure magnitude and societal impact requires institutional reform that makes wellbeing assessable, comparable, and consequential within budget processes, with Health well positioned to lead as a proof of concept.