How to make user testing incentives fair internationally

Question

I have some usability testing that is taking place in several different countries. The overall budget for incentives is set (in £) but dividing this equally between all countries and then converting it to their currency would mean that some countries end up a higher-value reward because of the economy.

Any ideas on how to split this fairly for everyone?

I thought about comparing the price of staple groceries which are hopefully hold a similar value across developed countries. UK data is common knowledge for me but I couldn't find comparable data for countries in Asia and America.

Any help would be much appreciated.

Answer 1

It's no formal index, but the Big Mac Index is probably one of the most fair and complete sources for this sort of data. The economist recently published an "adjusted" Big Mac Index to ajust for GDP per person which matches purchasing power a bit better than the classic BMI.

Answer 2

You can use the Big Mac Index to compare the purchasing power of different currencies in different countries.

Answer 3

If you are using local recruiters - I'd ask them.

Obviously the point of the incentive is to get people to turn up - so you might want to pay more in locations where you can't afford to have to re-run testing if there are no-shows.

Answer 4

A lot depends on how technical you want to get. The Big Mac Index is quick and dirty, but not very accurate.

The best bet would be to use the indices from the World Bank's International Comparison Program. the advantage here is that they show data for high middle and low incomes in each country, so you can really compare across your target groups.