What term refers to measuring poverty based on a household's income falling below the level necessary to sustain its members?

The term that refers to measuring poverty based on a household's income falling below the level necessary to sustain its members is "absolute poverty." This concept focuses on a fixed economic threshold that determines whether an individual's or household's income is sufficient to meet basic needs such as food, shelter, and clothing. Absolute poverty is often quantified using specific income levels established by governmental organizations or researchers which denote the minimum income required to live.

In contrast, relative poverty compares an individual's or household's income to the broader community, determining poverty based on the economic status of others and societal standards, rather than on a static threshold. The official poverty rate represents a statistical measure used to assess economic insufficiency, specifically in the context of national standards, while the poverty threshold is the specific income level that defines whether an individual or family is considered to be living in poverty. Thus, "absolute poverty" aptly captures the essence of the measurement based on whether income is sufficient to meet basic life-sustaining needs.