The essential data needed for creating a Lorenz curve includes income levels for individuals or households. This information is critical for assessing income inequality within a population. It helps in analyzing the distribution of wealth and identifying disparities among different socioeconomic groups. Researchers must have detailed income data sorted from lowest to highest earners to plot the curve accurately. The Lorenz curve visually represents the distribution of income or wealth within a population, highlighting the concentration of resources in specific segments. It is a powerful tool for policymakers and economists to understand and address inequality issues effectively.