CASSM project

Introduction p 5: CASSM in Design

CASSM is, first and foremost, an evaluative technique. So how does it fit within a design process? We do not have a process model (whew!), but our view is as follows:

Design evolution:

In design, you are often trying to make products fit better with the ways users are thinking about what they're doing. Users' thinking will be based on many factors such as

• the real-world 'things' they're working with
• the ways things have been described to them
• the ways they have experienced systems in the past.

You often want to exploit this thinking. CASSM helps you articulate the users' view and relate that to current systems in ways that should help you think about improving the fit for future generations of products.

Design revolution:

Sometimes, designing is about producing radically new ways of interacting. So what are the existing user concepts you can usefully invoke, and what are the new ones ... and for the new ones, how will you project them through the interface so that users can quickly make sense of them? CASSM helps identify

• where users are coming from
• how they currently think about the domain;

and hence ...

• what aspects a new design has to pay particular attention to,
• what prior understanding can be exploited
• what features can usefully be imported from existing similar systems (if any).

In summary, CASSM supports thinking about users' concepts, now and in the future, and effective design includes a careful balance of accommodating and exploiting existing concepts while nurturing the development of desirable new ones ... yet trying to avoid the development of undesirable or confusing concepts.

This page last modified 26 February, 2010 by Ann Blandford