The evidence in Charting Progress 2 comes from data collected by the UKMMAS Evidence Groups, which help fulfil our national and international obligations under the various policy initiatives and legislation. This also includes research undertaken at marine research institutes and universities across the UK and further afield. For the assessment of productive use of our seas, we also used economic information and statistics gathered from government agencies, regulatory authorities and the key industries that use the marine environment. The evidence is presented in detail in the four Feeder Reports which are available at: http://chartingprogress.defra.gov.uk/resources

Our conclusions about the status of UK seas depend critically on the extent and sufficiency of the available evidence. However, marine research and monitoring varies hugely in its spatial and temporal coverage. In some cases, such as for hazardous substances, we had robust data that have full quality assurance and internationally recognised standards. In other cases such as for marine litter, the data are less robust and are largely collected on a voluntary basis. Where data were simply not available, were not collected to a recognised standard or were too variable to allow us to draw any firm conclusions, we used expert judgement to estimate the likely status.