In open publications and standards on software requirements one can see lists of software quality attributes, which can be useful to define & measure in it projects. Yet these lists are of little help when it comes to the point where analyst needs to define specific requirement in numbers – for example, for usability or scalability. I will present my model for external & in use software quality, which proved to be useful. I will also provide instruction on how to select quality profile and how to specify it so that it can be measured. Presented model covers: - 14 classes of IT systems and respective profiles - 4 levels of quality - 12 quality attributes - 20 quality metrics Listeners will be given handouts with all necessary templates and instructions.