What are classfication codes?
Classification codes are used to describe or define an industrial activity in publications and databases.
Official publications produced by governments and international organisations, including national and international statistical offices, will generally make use of these codes, as do many commercial databases.
Countries, international organizations and publishers have developed independent classification schemes and although there is now greater harmonization in the EU there are still a number of classification schemes in use around the world.
Codes are periodically revised to reflect industrial and economic development and so it is important when carrying out research using data for a range of years to be aware of revisions