Toward a Post-Sectoral Specialization Index: Genealogy, Current State, and Research Trajectory

This working paper introduces the Post-Sectoral Specialization Index as a conceptual and methodological framework for diagnosing structural transformation beyond classical sectoral models. It develops out of earlier work on the Tertiarization Index, sectoral efficiency, and the Post-Sectoral Gap, but shifts the analytical focus from sectoral transition to post-sectoral divergence. Classical accounts of economic development often describe transformation as a sequence from agriculture to industry and then to services. In many such approaches, employment shares function as the primary indicator of structural change. This paper argues that this employment-centred perspective is no longer sufficient under post-sectoral conditions. Employment, value creation, productivity, institutional control, and spatial use increasingly diverge. The proposed index is not presented as a finalized empirical measurement tool. It is introduced as a diagnostic matrix. Its purpose is to identify where labour allocation, value-added structure, relative productivity, institutional control, and spatial manifestation begin to decouple in ways that indicate post-sectoral transformation. The framework preserves the original tertiarization logic by distinguishing between employment-based and value-added-based measures. The employment-based variant is defined as: Wt-E = Employment Sector III / Employment Sector II Wt-E measures the relation between service-sector employment and industrial employment. It preserves the original tertiarization logic, but limits it to the employment dimension. The value-added-based variant is defined as: Wt-VA = Value Added Sector III / Value Added Sector II Wt-VA measures the relation between service-sector value added and industrial value added. It captures whether value creation shifts in parallel with, or independently from, employment. The proposed divergence measure is defined as: PSDI = Wt-VA - Wt-E The Post-Sectoral Divergence Index indicates the degree to which value-added structure diverges from employment structure. A rising divergence suggests that an economy is moving from sectoral transition toward post-sectoral decoupling. The paper further connects this framework to spatial planning. Brownfields are treated as spatial test sites of post-sectoral adaptability. They are not merely residual spaces of industrial society, but sites where industrial, logistical, digital, energetic, residential, and resilience-related functions may recombine. In this sense, brownfields provide a concrete spatial field in which post-sectoral divergence becomes visible. The first proposed empirical step is a deliberately minimal comparative dataset for Germany, the United Kingdom, the United States, and China. The purpose of this first dataset is not comprehensive coverage, but proof of diagnostic structure. Later extensions may include regional deepening, especially Baden-Württemberg and the Neckar Valley, as well as brownfield-oriented applications. The originality of the framework does not lie in inventing sectoral analysis. It lies in shifting the analytical focus from sectoral transition to post-sectoral divergence. The paper treats the index as an operational arm of post-sectoral theory: a structured attempt to detect where sectoral transformation becomes post-sectoral divergence and where this divergence begins to reshape space. Author keywords (free terms): Post-Sectoral Specialization Index; Tertiarization Index; sectoral efficiency; Post-Sectoral Gap; employment-value decoupling; post-sectoral divergence; brownfield adaptability; structural transformation; spatial planning; regional transformation; value-added structure; relative productivity; Beyond Sectors. Internal reference: CB_PSI_01 (v0.1) Terminological note: The title “Post-Sectoral Specialization Index” is used in this v0.1 concept paper as a provisional formulation. The analytical focus of the paper is not classical sectoral specialization, but post-sectoral divergence, especially employment-value decoupling, relative productivity concentration, and spatial manifestation. A future version may therefore refine the title toward “Post-Sectoral Divergence Index.”