Idea Generation

The approach we describe here involves using two different mechanisms for systematic idea generation. One involves systematic explicit reasoning via serial processing. The other involves recognising underlying similarities via pattern matching.

This section describes two methods based on these mechanisms; systematic constraint relaxation, and pattern matching. Both these methods are designed to give all members in a session an equal chance to contribute, and to give all ideas an equal chance to be considered, rather than having the session dominated by the loudest or most opinionated group members. Both methods are also designed to encourage a broad range of ideas, rather than stopping at the first promising idea.

This section describes methods for generating ideas. Best practice in idea generation is to generate ideas first, and to develop and/or assess them afterwards in a separate session. Methods such as idea commenting help to extend and explore an initial idea; methods such as Multi-Criteria Decision-Making enable systematic quantitative comparison of different ideas against selected criteria.

This approach gives systematic coverage of both mechanisms for idea generation. It also enables fast, efficient assessment of the ideas that are generated.

For very quick informal generation of ideas for solving a specific problem, you may also find hexagonal cards useful.

The composite image below shows a constraint relaxation list, an idea generation card, and an idea commenting sheet.


Idea generation via constraint relaxation

  • A list of key constraints (e.g. the stairs must be inside the building) in the format shown below, which makes it easier to keep track.
  • A hard copy of the list for each member of the idea generation group, or one large copy visible to everyone on a poster or PowerPoint slide.

Relax the first constraint.

  • Tell the group to imagine that the first constraint no longer applies.
  • Encourage the group to suggest ways of solving the problem without the first constraint.
  • Use only positive phrasing; encourage even wild ideas. You can weed out the bad ones later. The best ideas often look wild at first sight.
  • Record the ideas that are generated. You can either appoint a scribe, or ask group members to write down their ideas.


Restore the first constraint, and relax the second one.

The simplest approach is to relax only one constraint at a time. But sometimes you’ll notice a good solution that requires relaxing more than one constraint simultaneously.

  • Continue to the end of the list of constraints.
  • Collate ideas, for development and/or assessment in a separate session.


Idea generation via pattern matching

What you need:

A set of random images, either as soft copy slides or on one card per image, such as the ones below. We have obtained good results with as few as eight cards, but we advise using more. Participants are likely to become mentally tired after about twenty or thirty cards; you can experiment with the number and see what works best for your context.

Tip: Resist the temptation to select images that are related to the problem you’re trying to tackle. This method works much better with apparently unrelated images.

Get the group members seated.

  • If using a screen, make sure everyone can see the screen clearly.
  • If using cards, give everyone a copy of the same pack of cards.

There are other variants, such as having a large pack of cards in the middle of the table, and allowing group members to pull one card at a time out of the pack. For simplicity, we’ll describe the variant where each group member has a copy of the same pack of cards.


Run the slideshow, or call out the number of the card that the group members should look at (so that they all finish at the same time).

If using a slideshow: allow an agreed time (e.g. 30 seconds per slide) for group members to see each card and to write ideas down.

If using cards: ask each group member to look at each card for an agreed time (e.g. thirty seconds).

  • Whenever a group member has an idea, they write that idea down, without telling the other group members what it is.
  • Continue to the end of the slideshow or pack.
  • Collate ideas for development and/or assessment in another session.


Where next?

You can assess the ideas in various ways, including:

Idea commenting where each idea is written on a separate sheet, and a group of people write comments on each idea, like an online comment thread.

Multi-Criteria Decision Making where you list the ideas on one axis of a spreadsheet, and assess them against relevant criteria (e.g. cost or feasibility) listed  on the other axis.


Other methods that complement idea generation

Upward laddering on goals and values, to find out why the participant considers something important.

Downward laddering on explanations, to find out what the participant means by a particular term.