We have talked a lot this week about the gains from trade. A recent summary of new research by Nigai (2016) shows that differences in consumption across different consumers within a country are an important source of differences in public perceptions about the gains from trade. For example, in countries where many consumers may already spend large portions of their budget on food, trade involving large amounts of agriculture exports may have harmful consumption effects on poor households. The article uses a simulation technique (using theory-based predictions calibrated to observed data) to show that the gains from trade may vary greatly across the income distribution of a country, and the errors of assuming a "representative consumer" may vary across countries as well.
The article exposes two problems with common claims about the gains from trade that we have discussed in class. The first is that preferences can be easily aggregated. Even if preferences are not too different for different consumers, differences in income may result in differences in outcomes in terms of households' responses to price changes. This is because households' preferences are not homothetic, i.e. households do not spend a constant proportion of their income on primary goods (like food or energy) as they do on manufactured goods (like electronics or cars) - the poor tend to spend a lot higher proportion on food.
Even more importantly, since different consumers have different incomes, price changes impact them differently. We mentioned this with respect to the gains from trade: Households that spend a lot on the exported good will "lose" in their consumption (even if their income remains constant), where households that spend a lot on the imported good will "win" in consumption. The reverse is true for households involved with production of exports and imports. The worst case scenario, of course would be to consume a high proportion of your income with exported goods, but work in a sector that competes with imports.