We review past and current psychometric theories about intelligence and critically evaluate the usefulness of modern IQ tests in guiding decisions within an educational context. To accomplish this we consider whether knowledge about intelligence extends beyond mere description to provide a scientific framework for further advancing our understanding. We conclude that it does. We also conclude that current evidence supports the importance of general ability, as well as several different specific abilities, although whether emotional intelligence can yet be affirmed is not clear. Additionally, we conclude that creativity is something separate from intelligence. Despite strong evidence that intelligence and IQ must be different constructs, we conclude that the latter provides the best available means for investigating and making decisions about the former, with higher validity for this purpose than has frequently been realised. We therefore recommend aptitude and achievement testing as useful tools for educational settings, provided they sample a broad range of different intellectual domains in addition to general ability. We also emphasise the importance of such tests being culturally compatible with the child's background.