Following Asness et al. (2013), we consider quality as the consistent ability to generate strong future cash flows. We assess quality from several perspectives: profitability, operating efficiency, earnings quality (accruals) and leverage. Current profitability is related to future levels of profitability and the persistency of profitability is a key indicator of quality. Profitability improvements that are the result of increased operating efficiency or asset utilisation are likely to be more sustainable and therefore symptomatic of quality.