If ex-ante Aggregate demand is less than ex-ante Aggregate Supply (AD < AS), it means households are incurring less expenditure on goods and services than the flow of goods and services in the economy.
Effect on output: Goods will remain unsold with the producers and to clear the stocks producers will plan to cut down the production. So, output will fall in the economy.
Effect on Employment: Plan to reduce output will lead to fall in employment level in the country. Producers will start laying off employees.
Effect on Income: Retrenchment or lay off employees will lead to fall in income level of the country. National Income and per capita income of country will fall.