Many software projects deliver low quality, because it is too difficult to estimate software quality at design time. In this web site we document what effects design decisions have on software quality. The web site has the structure of a design space, which is a tree of design problems, solution options and their effects. It is based on literature study. Click here for a list of literature used so far. The design space can be used by practicing designers and by researchers. An explanation of the goals and structure of the space is given here. To start exploring the design space, click on Information System Design Space Root in the menu. For an overview of the design space, click on Information System Design Space Outline in the menu.