DECONSTRUCTING HTA
For more than four decades, health technology assessment (HTA) has relied upon a quantitative framework built around health-state preferences, utility algorithms, quality-adjusted life years (QALYs) and cost-per-QALY claims. These procedures have become institutionalized through reference cases, professional guidelines and graduate education. Yet their foundational measurement properties have never been adequately demonstrated.
The fundamental failure is not simply that arithmetic has preceded measurement. Legacy HTA has developed largely without recognizing the requirements of representational measurement and the theory of measurement scales. Numerical scores have been treated as measures without establishing the attributes they represent, their scale properties or the arithmetic operations they legitimately support. Statistical estimation, model validation and sensitivity analysis cannot remedy the absence of demonstrated interval and ratio measurement properties.
Deconstruction is therefore warranted because the scientific foundations of legacy HTA must be examined before its quantitative claims can be accepted. The appropriate method is process validation: a sequential assessment of each procedure against the axioms of representational measurement, including unidimensionality, invariance, admissible transformations, dimensional homogeneity and commensurability. Failure at any indispensable stage requires a mandatory STOP decision.
The objective is not to improve legacy models but to determine whether their quantitative claims are scientifically defensible. Under the standards of process validation, they are not. HTA is at a crossroads: continue with measurement-free numerical storytelling or transition to an analytical framework for therapy-impact assessment that meets the measurement standards of normal science. Reconstruction must begin with explicitly defined attributes and validated measurement procedures.
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