Whilst reporting on numerical-based activities such as income versus expenditure is relatively straightforward for organisations seeking to understand their progress in meeting their objectives, it is more difficult to present nonnumerical-based activities such as conservation and preservation
in similar terms. However, without numerical key performance indicators (KPIs) conservation activities risk becoming invisible in organisational reporting, compared to activities that are easier to measure, such as, in heritage organisations that open their assets to the public, visitor numbers
and income. The National Trust for England, Wales and Northern Ireland has devised a numerical measure to describe relative performance in reaching defined conservation standards, benchmarked against external standards such as the Canadian Conservation Institute's 'Agents of Deterioration'
framework and the UK's Museum Accreditation Scheme. This paper describes the development and practice of this measure, the Conservation Performance Indicator (CPI), with particular reference to cultural heritage features, such as historic interiors, collections, buildings and archaeology,
and in the context of the evolution of a devolved structure.