Dynamic efficiency 

Consumer Price Index and Retail Price Index - key measurements of inflation.

Mr Miles Harris but what does it actually measure? Does it measure consumers’ purchasing power for CPI and what’s for RPI?

Hey. In it's simplest form think of it as tax & spend. Usually, this involves expansionary fiscal policy in response to a recession or contraction of GDP.

Mr Miles Harris what is fiscal policy in simple terms ?

Mr Miles Harris so Keynesian economic is to do with total spending in an economy by the government?

@@randomgaminghd5536 Keynes proposed government stimulus spending to help boost aggregate demand. It's worth remembering that he also suggested a fiscal surplus should be run when the economy is expanding. Fiscal policy is just government spending and taxation and it's influence on aggregate demand and incentives

Mr Miles Harris one more thing. What is aggregate demand and aggregate supply?