What does HDI stand for, which is used by the United Nations to measure levels of development?

The correct answer is Human Development Index. HDI is a composite statistic of life expectancy, education, and per capita income indicators, which are used to rank countries into four tiers of human development. This index was developed by the United Nations as a measure to assess the social and economic development levels of countries.

The use of HDI allows for a more nuanced understanding of development beyond just economic indicators such as GDP, as it incorporates factors that contribute to overall quality of life. This makes HDI a critical tool for policymakers and researchers in evaluating progress and planning for future development strategies.

Other choices, while they may seem plausible, do not accurately reflect the established terminology. For instance, "Human Development Indicator" and "Human Development Integration" do not align with the recognized term used in international research and reporting. "Human Dynamics Index" is also not a valid term in the context of measuring human development. Therefore, Human Development Index is the correct and widely accepted term that encapsulates this measurement of development.