Complete coverage of economic production is a vital aspect of the quality of the national accounts.
This exhaustiveness is hard to achieve because of the difficulties in accounting for certain types of
productive activities. Activities that are missing from the basic data used to compile the national
accounts because they are underground, illegal, informal, household production for own final use, or
due to deficiencies in the basic data collection system are referred to as non-observed. They are said to
comprise the non-observed economy (NOE), and including them in the national accounts is referred to as
measurement of the NOE.
Given the wide range of possible approaches to NOE measurement, there is a need to identify and
promote international best practice. This is the aim of the Handbook. It presents a systematic strategy
for achieving exhaustive estimates of gross domestic product that is consistent with international
standards and, in particular, with the 1993 System of National Accounts.

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