Absolute poverty, also known as subsistence poverty, defines a condition where individuals or families lack the minimal resources to meet their basic needs for survival, including food, shelter, warmth, and safety. This standard is based on a minimum level of subsistence below which families should not be expected to exist. It signifies a severe deprivation of essential necessities required for human well-being. The measurement of absolute poverty often involves a fixed income threshold that remains constant over time, although the specific level can vary between countries based on their economic conditions. The World Bank defines extreme poverty as living on less than US $1.25 or $1.90 a day. While useful for tracking income changes over time, this measure may not fully capture the realities of living in poverty, such as the inability to buy in bulk or social and cultural needs.