The study looked at how immigrants in the UK have been earning money compared to native-born people from 1978 to 2006. They found that immigrants who arrived more recently tend to earn more money when they first come to the UK. Also, these newer immigrants catch up to native-born people's earnings faster than immigrants who arrived earlier. It used data from many years to figure this out. Earnings grow the fastest in the first 10 years for immigrants, but then slow down after 30 years.