Table 1. Several major axes of variation characterize the diversity of purpose and approaches adopted in scenario exercises. The two columns represent the ends of a continuum. Most scenario exercises lie between these endpoints. Note that the different axes do not necessarily co-vary, i.e., the elements in each column need not co-occur. For example, an exploratory scenario could be motivated by either scientific inquiry or policy support (table adapted from Ducot and Lubben 1980, Bunn and Salo 1993, Wollenberg et al. 2000, van Notten et al. 2003).


Dimensions along which scenarios vary Range of variation
Purpose Exploratory, investigate uncertainties and drivers of change Decision support, test robustness of policies
Motivation Scientific inquiry Policy support
Focus On process: development of storylines On outcome: implications of storylines for decision making
Inclusion of norms Normative, e.g., scenarios reflect the desired and “good” or the undesired and “bad” Descriptive, not based on social preferences
Approach Quantitative, “hard,” formal models: statistical forecasting, trend-impact analysis, cross-impact analysis Qualitative, “soft” methods: visioning, intuitive logic, storytelling
Source of information Formal, rational, scientific observation Judgment and intuition of decision makers, intuitive, local knowledge systems and world views
Level of uncertainty Low High
Number of focal scales Single scale Multiple scales
Links between scales Loosely linked: perspectives, uncertainties, and drivers from each scale partially inform scenario exercises at other scales Tightly coupled: perspectives, uncertainties, and drivers from each scale strongly inform the scenario exercises at other scales
Number of storylines One Multiple (3–9, typically 3–5)
Starting point of storyline Future, uses backward inference or “backcasting,” deductive Present, uses future inference, inductive, builds from knowledge of roles and environmental trends
Endpoint of storyline “Snapshot” at one future point in time Story of events linked from present to future
Driving forces Underlying (exogenous, external): hard or impossible to control by stakeholders Proximate (endogenous, internal): controllable to some extent by stakeholders
Dynamics Simple Complex, includes thresholds and feedbacks
Stakeholders as participants Active participants in construction and evaluation, i.e., participatory scenarios Passive objects of analysis, i.e., expert-driven scenarios
Stakeholders as audience No communication strategy in mind Targeted communication strategy integral to design, e.g., policy briefings, drama, editorials