Five Reasons for Scenario-Based Design

Summary

Carroll argues that scenario-based design helps designers manage five recurring challenges in information technology design: balancing action with reflection, responding to fluid requirements, understanding the many consequences of design moves, developing knowledge when formal technical guidance lags practice, and resisting external constraints that distract from users. Scenarios are stories of people pursuing goals in concrete contexts; because they are vivid but revisable, they support reflection-in-action, multiple perspectives, stakeholder participation, and sustained attention to users' work and experience.

Important Keywords

Scenario-based design: using stories of people pursuing goals in concrete contexts to guide and reflect on system design.
Human-computer interaction: the field concerned with designing and understanding interactive systems in use.
Reflection-in-action: thinking through design moves while acting, supported by concrete scenarios.
Design fluidity: the changing, uncertain nature of design problems and requirements.
User activity: the concrete goals, actions, and contexts that scenarios keep visible.
Work-oriented design: design focused on supporting people's real work practices.
Stakeholders: people whose perspectives and consequences should be considered in a design scenario.
Design rationale: the reasons, trade-offs, and consequences attached to design decisions.
Requirements: descriptions of what a system should support, kept revisable through scenarios.
Participatory design: involving users and stakeholders in shaping and evaluating design scenarios.
Scenario: narrative description of use in context.
Design problem fluidity: the problem changes as design understanding and solutions evolve.
Experience-centered scenario: scenario that includes emotions, meanings, and social relations, not only task steps.
External constraint: organizational, technical, ethical, social, or business factor shaping design.

Important Concepts

Scenarios as stories: scenarios describe people, settings, goals, actions, events, and consequences in situations of use.
Reflection in design: constructing scenarios exposes assumptions about users, functionality, and experience while design work is still underway.
Concrete but flexible representation: scenarios fix a provisional interpretation of a design situation while remaining rough, incomplete, and easy to revise.
Multiple views: the same scenario can be elaborated as task, cognitive, functional, system, usability, or consequence-oriented views.
Knowledge development: scenarios can be abstracted, categorized, and reused as patterns or candidate generalizations across design problems.
Work orientation: scenarios anchor design discussion in users' activities and needs, helping stakeholders participate and helping designers avoid serving the wrong client or tidy but irrelevant problems.
Scenarios are stories about people, goals, context, events, and technology use.
They help designers externalize the design space, anchor requirements in practice, explore consequences, communicate concepts, and support shared reflection.
Scenario elements include setting/context, agents/actors, goals/objectives, plot/actions/events, and system state.
Experience-centered scenarios add motivations, feelings, meanings, values, and social relations.
Carroll's five reasons for scenario-based design are action versus reflection, design problem fluidity, design moves having many effects, scientific knowledge lagging design application, and external constraints.

Examples

An accountant rearranges a large spreadsheet, opens a covered folder, and positions a memo so the memo and budget can be examined together; the example reveals requirements for window management and application switching.
A student named Harry explores a multimedia education system by watching the Tacoma Narrows Bridge collapse, saving and annotating the clip, querying for other harmonic-motion examples, and moving to a flute and piccolo case study.
Harry's speech annotations make personal metadata easy to add but difficult to search later, illustrating how one design feature can have both desirable and undesirable consequences.
The Catgut Society's treble violin design shows how one move, adding rib holes, led to material changes and new acoustic problems affecting musicians, makers, and listeners.