The paper ‘Surveys concerning informal sector and their use by national accounts systems: some points for discussion’ by Mr. Rodrigo Negrete discusses the question of sample weighting based on population weights for estimation of economic variables while handling informal mixed household-enterprise surveys in relation to the data requirements of National Accounts. The problem might be real if the SNA scheme is based on Industries Sectors but might become fictitious when working under Institutional Sectors. The author discussed the problem of non-response bias in the informal sector surveys under the institutional framework of SNA. Based on the Mexican experience, the author points out that the pattern of non-response is not random but is higher in the upper layers of informal sector and asserts that a conceptual analysis is essential for non-response. Mixed surveys provide such a conceptual analysis.