P Poverty Lines and Their Role in Reducing Poverty John H. McKendrick Scottish Poverty and Inequality Research Unit, Glasgow Caledonian University, Glasgow, UK Synonyms Breadline; Poverty threshold Definitions Poverty line is a value that is understood to be the point of transition between living in poverty and not living in poverty. Typically, the poverty line is defined using levels of household income. It can be set at all geographical scales, although it is most commonly defined as either a national pov- erty line or an international (global) poverty line. The International Poverty Line is most closely associated with the World Bank’ s $1 a day stan- dard (and its uprating after 1990). The World Bank’ s International Poverty Line is generally understood to be the universal standard for deter- mining absolute poverty. A National Poverty Line is a value that is understood to be the point of transition between living in poverty and not living in poverty within a particular nation state. National poverty lines can be conceived using absolute poverty or relative poverty. Poverty Lines Poverty lines are essentially thresholds – points that mark the transition between whether or not the subject of study is considered to be living in poverty. Poverty lines are most commonly con- ceived in monetary terms, with the household or individual as the unit of analysis. The threshold value can be determined by what is actually con- sumed (or what, in theory, is considered necessary to consume), but more typically denotes what is earned (or what, in theory, is considered the level of income required to consume what is deemed necessary). Thus, and taking the example of household income, if the poverty line is set at $1/day, then a household income of 99 cents/day (or less) would determine that all within that household were living in poverty, whereas a household income of $1/day (or more) would determine that all within that household were not. Poverty lines (or thresholds) can also be deter- mined using metrics other than income, e.g., possession or not of “necessities”, or using a combination of income alongside other metrics. Furthermore, this threshold can be defined to a universal standard or can be contextualized to circumstance. Poverty lines can be used to com- pare the incidence of poverty across geographies (world regions, nations grouped by income status, nation states, or subnational geographies) or to compare variations in the incidence of poverty within geographies (for example, for subpop- ulations defined by socioeconomic character). © Springer Nature Switzerland AG 2020 W. Leal Filho et al. (eds.), No Poverty , Encyclopedia of the UN Sustainable Development Goals, https://doi.org/10.1007/978-3-319-69625-6_91-1