Encouraging collaboration on technology development is particularly pertinent when addressing global climate change or regional pollution. Importantly, international collaboration in research and technology can help local businesses take advantage of existing technologies (i.e. help build local absorptive capacity). This, in turn, helps increase the uptake of cleaner technologies globally. Inventors seek protection for their inventions in countries where they expect to invest, export or otherwise market their products. Often they do so in multiple jurisdictions (geographic markets). Patent data present a number of attractive properties compared to other alternative metrics of innovation. They are widely available, quantitative, comparable and outputoriented. They can also be disaggregated – an important advantage when analysing environment-related technologies. At the same time, not all innovations or inventions are patented. Further, the number of patents by itself does not indicate their relative importance and impact. Analytical techniques have been developed to overcome some of these limitations (e.g. patent family size, relative technological advantage). Yet it is important to carefully interpret these indicators.

Environmentally related taxes are an important instrument for governments to shape relative prices of goods and services. The characteristics of such taxes included in the database (e.g. revenue, tax base, tax rates, exemptions, etc.) are used to construct the environmentally related tax revenues with a breakdown by environmental domain: energy products (including vehicle fuels); motor vehicles and transport services; measured or estimated emissions to air and water, ozone depleting substances, certain non-point sources of water pollution, waste management and noise, as well as management of water, land, soil, forests, biodiversity, wildlife and fish stocks. The data have been cross-validated and complemented with Revenue statistics from the OECD Tax statistics database and official national sources.