The materials science community has identified nanoparticle dispersion as a primary challenge area for the advancement of polymer nanocomposites technology. Although nanoparticle dispersion can significantly impact important engineering properties, it is not itself a quantifiable property: qualitative TEM image assessments remain as the 'gold standard' for dispersion characterization. While numerous quantitative dispersion analyses have been proposed, they have often proven Cumbersome, system specific and unreflective of the proposed benefits of nanoparticle reinforcement. No single quantitative method has been adopted by the community to date and inferences about processing and dispersion effects generally require subjective analysis. This paper presents a quantitative dispersion characterization method which 1) makes use of standard TEM dispersion images; 2) directly reflects proposed nanoscale reinforcement mechanisms: 3) outputs a single performance metric. By quantitatively isolating dispersion effects, this technique may help to link disparate studies in the literature while providing defensible quantitative insights into nanoscale reinforcement mechanisms. (C) 2009 Elsevier Ltd. All rights reserved.