The SARM Quality Model is a simple hierarchical model with six Quality Characteristics at the top level, which are further divided into nineteen sub-characteristics. Between them, they aim to cover a 360 degree view of the quality characteristics that might be desired in any given system or service. This model was inspired by ISO 9126-1, which has now been deprecated, though it is deliberately somewhat simpler. A description of each of the Quality Characteristics and their constituent sub-characteristics is available for download here.
This model is build in to the SARM spreadsheet tool, but it can be amended or replaced to suit individual requirements. For example, some organisations may wish to adopt ISO 25010 or ISO 25011, if they are licensed to do so. More details of how to make this change can be found here.