(Two topics): Benchmarking Building Performance: In a variety of voluntary and regulatory initiatives around the globe, including the introduction of the European Building Performance Directive, the question of how to assess the performance of commercial buildings has become a critical issue. There are presently a number of initiatives for the assessment of actual building performance internationally, including in particular US Energy Star Buildings rating tools and the Australian Building Greenhouse Rating scheme. These schemes seek to assess building energy performance on the basis of actual achieved results, which takes into account not only the theory of how well a design works but also the quality and fidelity of delivery, commissioning, operation and maintenance. It has been shown that in virtually identical buildings, with very similar systems, equipment, and space usage patterns, differences in control, operation and maintenance can generate dramatic impacts on the energy performance of the building. Given the known dissonances between theoretical performance and actual performance true operational performance-based assessment is essential if policy initiatives are to be assured of delivering actual benefits. Such assessment also has the strong benefit of being somewhat cheaper than design based approaches. In this paper, the various empirical benchmarking schemes around the world and in development are identified and briefly scoped. A summary of the benefits and problems of empirical benchmarking are discussed, and solutions and examples drawn from key existing schemes are presented. The Australian Building Greenhouse Rating Scheme: The Australian Building Greenhouse Rating (ABGR) scheme is Australia's performance based benchmarking system for office buildings. Launched in 1999, the scheme has become a key component of the office building market and has achieved a remarkable level of penetration with very limited support resources. The scheme uses a simple five star scale to communicate the energy efficiency of a building to the general public and non-technical decision makers. Supported by a largely self-funding implementation structure, ABGR is both a market transformation tool and a technical tool that enables the efficiency of a building to be reliably determined from simple inputs.