This scenario building technique is a part of the GBN Approach. It is one of the most well-known and simplest scenario techniques that produces rich narratives. It begins by ranking change drivers (selected using e.g. the STEEP technique) by their importance and uncertainty. Usually two of up to three of the highest ranking drivers are singled out as 'critical uncertainties'. These are used to plot horizontal and vertical axes, which represent the spectrum of possibilities between the extreme poles of the selected drivers. Contrasting scenarios are then created based on the combinations of critical uncertainties and other internal and external factors.

This technique tends to produce exaggerated versions of the present and can therefore shed light on the current situation with reference to the chosen critical uncertainties. Reality tends to be found in a cross-section of the four quadrants, with each quadrant representing a seed of a possible future. Our actions in the present can decide which future is more likely to unfold. The technique rarely produces radical breaks or surprises, but it can uncover what really matters to people and what they're most unsure of. It helps structure conversations, particularly about the present and very near future.

1. Rank driving forces by their importance and uncertainty: Identify the most important driving forces for the outcome of your key question or issue. You can rank them on a scale from 1–10 from least to most important. Alternatively you can use a more relative measure (e.g. drawing a horizontal line and placing the drivers from left to right: important → very important → extremely important → essential.
2. Identify which of the most important drivers are the most uncertain for the success of your core question or issue. Some drivers are likely to remain more or less fixed, constant and 'certain', like demographics, while others are mostly in flux and quite unpredictable, such as public opinion. You can rank the uncertainty of the drivers on a scale from 1–10, from least to most uncertain. Alternatively, you can use a more relative measure. One of the ways is to draw a diamond, with importance as one axes and uncertainty as the second one. By the end of this exercise, the most important and uncertain drivers will be in the top tip of the diamond, so they can be visually chosen.
3. List the drivers on a scale from most to least important and uncertain. Select 1–3 (usually 2) of the 'most important and most uncertain' drivers. These are your critical uncertainties which will constitute the axes of your scenarios.
4. Think about each of the critical uncertainties as a continuum. For example, if you chose 'happiness' as one important and uncertain factor, your continuum might be from 'an ocean of tears' at one end to 'all smiles' at the other.
5. Plot the axes on a large piece of paper. If you have just one critical uncertainty, you’ll create two scenarios along a spectrum of one line, with two you’ll create a matrix and with three a volume. For more than three we would suggest creating multiple matrices of two axes each. NOTE: You can choose more than two critical uncertainties, but that tends to make the process more complicated (you’ll have to develop multiple scenario matrices, or work in more than two dimensions, which participants tend to find difficult to hold in their heads).
6. Scenarios: review what would happen to each of your critical uncertainties in different scenarios. Bring different change drivers and local factors into the scenarios. What would happen to them in different worlds? How did the wider world evolve from the present to this particular future? How did your local situation change? Who are the main protagonists in this world? Come up with an outline, a 'skeleton' of each narrative with all participants. This can be short and succinct, but should capture the 'essence' of the scenario.
7. From these scenario skeletons you can write out the scenarios as short stories or moodboards. You can do this in smaller groups, or individuals can volunteer to flesh out the stories after the workshop and send them to others for edits and suggestions.

• GBN Approach
• Peter Schwartz: The Art of the Long View (and a summary)