A fall in the real exchange rate can increase demand for domestic output in two main ways. The volume of exports – which become cheaper – is boosted. And goods and services that were previously imported can instead be supplied by domestic producers, which become more competitive as the price of imports rises. Economists call the second effect ‘import substitution’. Using data from Supply-Use tables can help us better understand the process of import substitution, in particular by examining how the composition of expenditure has influenced imports. Doing so shows that the import substitution effect of the 2008-09 depreciation was partly masked by other, co-incident factors.