An extract from the resolution on statistics of employment in the informal sector adopted by the Fifteenth International Conference of Labour Statisticians (January 1993) is reproduced as an annex to chapter IV in the 1993 SNA. The resolution, among other things, provides an international statistical definition of the informal sector. However, the SNA does not amplify on the definition or provide guidance on its application in a national accounting context. Given that the informal sector accounts for a substantial portion of production in many countries, such guidance has often been requested. The review should consider whether the updated SNA can provide guidance drawing on work by the Delhi Group on Informal Sector Statistics and by ILO, UNECE, IMF, the Commonwealth of Independent States, and OECD in preparing Measuring the Non-observed Economy: A Handbook.