The 2015 Trends in Maths and Science Study (Timss) gives us a detailed breakdown of pupil performance in maths and science across 57 countries and 7 states or provinces. It measures performance in these subjects at the 4th and 8th grades of school (Year 5s, 9-10 year olds, and year 9s, 13-14 year olds, in England). Many commentators and professionals argue that international comparisons such as Timss and its big sister Pisa serve little purpose in assessing the performance of a single country because, after all, it is context that matters. Can we reliably compare a pupil in Knowsley to a pupil in Shanghai? Are test scores in a single year, in two subjects, enough tell us how well government is serving its’ pupils and future workforce? And do these tests actually mean anything for long term economic performance?