Scenarios - Principles and General Procedures


The scenario technique generates a narrative description of the future state(s) of the system. The format is the base system state description and one or more intermediate images, together with a description of the external context and the driving forces behind the forecasted changes.

One or more scenarios may be constructed: several alternative state scenarios for a single point in time, or, one (or perhaps two) transient scenarios, which forecast the effects of different policies on the evolution of system conditions. Decision makers and interested parties may compare these scenarios for review.


Main process:

The first element of scenario analysis is an interactive team process of creating building blocks for the scenarios. This process is generally carried out in a two-day workshop away from the usual working environment. The second element, the development of compelling scenario stories from this initial material through background research exploring the implications of the stories is less participatory by nature and usually performed by a small team of scenario analysts. In view of the focus of the current report on participation, we will concentrate on the scenario workshops themselves.

The first step in the process is to identify the key issues or questions relevant to the organisation and the time frame associated with the focal issue(s). This is followed by a brainstorming exercise to surface ideas associated with the issues under concern. From this brainstorming, driving forces and key trends are identified by clustering the brainstorm ideas into common themes. Often these are social, cultural, technological, economic, environmental and political, featuring the most significant events in the external environment; they will drive the plots of the scenarios and determine their outcome. A variety of procedures is developed for arriving at scenario plots from the key trends and driving forces. In general in the following way:

  • the driving forces and key trends are prioritised to determine those that are most important and uncertain;
  • these provide the themes for the plots;
  • a variety of scenario plots is then created from this limited number of selected themes;
  • once the themes are identified the group completes each scenario – tracing the narrative line from a beginning to an end.

The follow up to the workshop output involves a period of interim research and reflection, writing up the scenarios and exploring their implications. The important driving forces, trends and uncertainties are researched.

Key definitions:

  • A system is a collection of components, which interact to achieve a common function
  • A state scenario describes conditions and events (the state of the system and the external context) at an single future point in time
  • A transient scenario forecasts the changes in and the alternative action on a system at various stages in the evolution of the system
  • The dimensions of a system are collections of its attributes, where each collection represents a major aspect of the system (e.g. political, economic, etc.)
  • The attributes of a system include the elements of components of the system and the interrelationships among them
  • A goal is a value judgement that satisfies one or more needs e.g. “to promote equality in schooling”
  • driving force is an attribute of a system which causes changes in the system state over time
  • The base system state is the set of current conditions, which describe the characteristics of the scenario
  • An intermediate image describes the state of the system after a time interval
  • The external context represent the constraints on the base system


Important assumptions:

A scenario is constructed by extrapolating future conditions from present conditions and foreseeable driving forces for change. Consequently, a fundamental assumption concerning dynamic system behaviour is implied: a system exhibits current conditions that are the result of all the previous current and prior forces on the system. However, social systems are self-organizing and anticipatory, and the current system state may be influenced by anticipated future conditions. According for these factors in scenario construction requires that the analyst be aware of the possible effect of anticipated action on the future state of the system

Basic steps:

1. Construct the base system state

  • Identify the major sub-groups in the base system
  • Identify the attributes of the sub-groups
  • Choose one of the attributes as the driving force for the change in the system

2. Identify the external context

  • Formulate the hypotheses about the constraints on change in the base system state
  • Consider constraints that may change during the time span of the system

3. Develop the progression to the first intermediate image

  • Identify the trends in the interaction between attributes of the base system for the time intervals (5-10 years)
  • Identify any changes in the external constraints for the time interval
  • If the alternative or competing trends are likely, construct an intermediate image for the time n... for each major trend

4. Construct the intermediate image

  • Using the dimensions and attributes identified in step 1, describe the likely system state or conditions at time n...
  • Take into account the forces for change, the external constraints and the trends internal to the system

5. Repeat step 3 & 4 until the desired time span has been covered

  • The last intermediate image becomes the new base system state
  • To progress to the next intermediate image, consider changes for the interval time n.. to time n+...
  • End the scenario with the last intermediate image
If a normative scenario is being developed, the procedure in step 4 is inverted. Instead of predicting intermediate image, the analyst tries to identify the alternative action or policies that are necessary to achieve the desired system state. This is typically an iterative process, where the first one set of policies, the external trends of the system and the external context are used to forecast a likely progression. The discrepancy with the normative system state is then used to indicate alternative policies until the desired and the predicted intermediate image merge.

Figure 1: Basic Steps using Scenarios


files/images_static/result.jpg However, in many cases a simplified description of the step-by-step process is always possible.