The Psychology of Quality and More

The Force-Field Diagram

Quality Tools > Tools of the Trade > 2: The Force-Field Diagram

What's it for?

A common problem that often crops up in various business areas is one of a simple go-no go decision. Questions such as  'Shall we install a new machine?' or 'Is is worth continuing with this project?' are simple to ask, but regularly seem to result in endless rounds of meetings, arguments and more meetings.

Never fear, the Force-Field Diagram is a simple tool that you can use to help yourself or other people resolve such problems by weighing up the pros and cons of the situation and coming to a agreeable, balanced conclusion.

How does it work?

The Force-Field Diagram works by first identifying points for and against the argument and then organising and displaying them visually in a diagram, as below. Each argument is shown as an arrow, 'pushing' either in the 'for' or 'against' direction. Each of these argument may also have a different weight - for example, the fact that an old machine keeps breaking down may be more important than the ripost that it is easy to fix. This is highlighted by using longer arrows for more important points.

The complete diagram gives an overall picture of all forces 'for' the argument, pushing back the forces 'against' the argument. It is surprising how often that disputes that have raged for days or weeks are rapidly resolved as the diagram clearly shows more forces pushing in one direction or another. Even if it is not clear, it can be agreed by both sides that in the end, it will be a judgement call.

How to do it

1.     Gather together the people who have information about the problem.

2.     Write a statement that describes the decision or situation to be resolved. In particular, it should help points for and against the argument to be identified. Write this statement in the top-centre of the paper or whiteboard.

3.     Draw a vertical line below the statement, and write 'For' at the top on the left and 'Against' on the right.

4.     Ask the team to identify the key arguments for and against the problem.  Write these points on the left or on the right of the line, as appropriate. Do not yet draw any lines arrows under them.

5.       Identify the criteria to use for deciding on the importance of each item. For example, if the problem is about delivery times, the criteria may be, 'meets commitment to customer' and 'not too expensive'. If people cannot agree on criteria to use, it may highlight an underlying problem where they are using different criteria to judge the overall problem. It is usually worth taking some time to discuss and resolve this sub-problem.

6.     Take each argument in turn, discuss it, and use the criteria from step 5 to help identify how important it is. For an unimportant argument, draw a short arrow underneath it, pointing into the centre line. For an important item, draw a long arrow.

              You can get quite structured about this by having a scale of 1 to 5 to indicate the strength of the argument, and draw vertical dotted lines to show their position. This makes arrows easier to draw, as each will stop only at at dotted line.

7.     Stand back and look at the completed Force-Field Diagram. Does the answer jump out at you? If it is clear, then well and good. Otherwise spend more time discussing the individual forces, or find data to ensure the forces are based on fact, rather than opinion.

              If you used a scale in step 6, then you can add up the strength points from either side to give 'total strength' figures for the arguments for and against.

Overall, the Force-Field diagram is a practical and easy tool that can be used to help you find and explore the arguments for and against a single decision point.

Next time: Fishbones with Everything (Cause-Effect Diagram)

This article first appeared in Quality World, the journal of the Institute for Quality Assurance