The proposed definition of household discretionary budget relies on a poverty line to approximate the cost of basic needs.The societal poverty line was developed to acknowledge that estimated minimum cost of needs and social participation varies across countries over time, conditional on the overall level of economic development. This is important for the cross-country comparability requirement embedded in the global SDG monitoring framework.

The SPL is calibrated as the closest empirical fit to existing definitions of national poverty lines. Other international poverty lines that can be used to assess the cost of basic needs, including the one used in SDG indicator 1.1.1. The SPL definition includes the use of the international poverty line for some countries (as used by SDG indicator 1.1.1) but it allows the use of higher values using a formula that includes a fixed element and a relative gradient in consumption or income levels which is better align with the relative concept of poverty adopted as countries become richer.

For all these reasons, the SPL is preferred to any other poverty line for SDG reporting.  Other regional and national methods to define household discretionary budget and methods to estimate basic needs exist and are relevant to contextualize findings.