Refer to what is produced directly or immediately by an activity. Depending on their nature, outputs may, or may not be straightforward to measure. Thus, the number of hospital cases treated by a doctor is likely to be easier to measure than the advice on a policy issue submitted by a health administrator to his chief executive or minister, which can only be evaluated in a qualitative and essentially subjective way.
Organization for Economic Cooperation and Development (OECD), "Effects of European Union Accession, Part 1: Budgeting and Financial Control", OECD SIGMA Paper No. 19, Paris, March 1998