You should be able to explain/analyze (AO2) single indicators as ways to measure development (SL+HL)
Single indicators are ways to measure economic development, using just one variable. Examples include:
GDP/GNI per capita at Purchasing Power Parity: Measures the value of all finished goods and services the economy produces, divided by the amount of people in that economy, and adjusted for purchasing power.
Health and education indicators: Measures values such as average lifespan at birth and literacy rates.
Economic/social inequality indicators: Measures inequality levels, such as the Gini coefficient.
Energy indicators: Measures the availability of energy/electricity.
Environmental indicators: Measures values such as carbon emissions, temperature changes, deforestation, and air quality levels.
Because they only measure one variable, single indicators may be a bit superficial. Here are more examples
Composite indicators are ways to measure economic development, by combining multiple single indicators. This allows them to provide better insight into an economy's development. Examples include:
Human Development Index: Measures development using healthcare, education, and income levels.
Gender Inequality Index: Measures inequality using reproductive health, empowerment and labor market participation.
Inequality-Adjusted Human Development Index: The Human Development Index, but considers how its factors (healthcare, education, and income) is distributed in the population.
Happy Planet Index: Measures human and Earth's well-being using well-being, life expectancy, inequality, and ecological footprint.