This paper proposes a novel decomposition framework for pure technical efficiency within the Data Envelopment Analysis (DEA) approach. Building on the BCC model, we introduce input- and output-decomposed formulations (ID-BCC and OD-BCC) that preserve the radial structure and dual optimal weights while providing disaggregated efficiency measures. The proposed models enable the decomposition of pure technical efficiency into input-specific radial contraction factors and output-specific radial expansion potentials, respectively. Theoretical properties, including aggregation consistency and single-run computability, are formally established. Building on the decomposed CCR model results (ID-CCR and OD-CCR) for constant returns to scale (CRS) input- and output-orientated efficiency measures, we derive input and output scale efficiencies (ISE and OSE) as the ratios of ID-CCR to ID-BCC and OD-CCR to OD-BCC, respectively. An empirical illustration based on EU agricultural systems, using FAO data, provides evidence that inefficiency arises from heterogeneous sources, including input misallocation, output imbalance, and scale effects. By shifting the focus from inter-unit benchmarking to internal efficiency diagnosis, the approach enables each decision-making unit to identify targeted adjustment strategies. The paper advocates treating the proposed decomposition as a practical management tool.