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Grid Analysis: making a choice where many factors must be
balanced.
How to use tool:
Grid Analysis is a useful technique to use for making a
decision. It is most effective where you have a number of
good alternatives and many factors to take into account.
The first step is to list your options and then the
factors that are important for making the decision. Lay
these out in a table, with options as the row labels, and
factors as the column headings.
Next work out the relative importance of the factors in
your decision. Show these as numbers. We will use these to
weight your preferences by the importance of the factor.
These values may be obvious - if they are not, then use a
technique such as Paired Comparison Analysis to estimate
them.
The next step is to work your way across your table,
scoring each option for each of the important factors in
your decision. Score each option from 0 (poor) to 3 (very
good). Note that you do not have to have a different score
for each option - if none of them are good for a
particular factor in your decision, then all options
should score 0.
Now multiply each of your scores by the values for your
relative importance. This will give them the correct
overall weight in your decision.
Finally add up these weighted scores for your options. The
option that scores the highest wins!
Example:
A windsurfing enthusiast is about to replace his car. He
needs one that not only carries a board and sails, but
also that will be good for business travel. He has always
loved open-topped sports cars. No car he can find is good
for all three things.
His options are:
Criteria that he wants to consider are:
-
Cost
-
Ability to carry a sail board at normal driving speed
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Ability to store sails and equipment securely
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Comfort over long distances
-
Fun!
-
Nice look and build quality to car
Firstly he draws up the table shown in Figure 1, and
scores each option by how well it satisfies each factor:
|
Factors: |
Cost |
Board |
Storage |
Comfort |
Fun |
Look |
Total |
|
Weights: |
|
|
|
|
|
|
|
|
Sports Car |
1 |
0 |
0 |
1 |
3 |
3 |
|
|
4WD |
0 |
3 |
2 |
2 |
1 |
1 |
|
|
Family Car |
2 |
2 |
1 |
3 |
0 |
0 |
|
|
Estate Car |
2 |
3 |
3 |
3 |
0 |
1 |
|
Next he decides the relative weights for each of the
factors. He multiplies these by the scores already
entered, and totals them. This is shown in Figure 2:
|
Factors: |
Cost |
Board |
Storage |
Comfort |
Fun |
Look |
Total |
|
Weights: |
4 |
5 |
1 |
2 |
3 |
4 |
|
|
Sports Car |
4 |
0 |
0 |
2 |
9 |
12 |
27 |
|
4WD |
0 |
15 |
2 |
4 |
3 |
4 |
28 |
|
Family Car |
8 |
10 |
1 |
6 |
0 |
0 |
25 |
|
Estate Car |
8 |
15 |
3 |
6 |
0 |
4 |
36 |
This gives an interesting result - despite its lack of
fun, an estate car may be the best choice.
If the wind-surfer still feels unhappy with the decision,
maybe he has underestimated the importance of one of the
factors. Perhaps he should weight 'fun' by 7!
Key points:
Grid Analysis helps you to decide between several options
where many factors need to be taken into account.
To use the tool, lay out your options as rows on a table.
Set up the columns to show your factors. Allocate weights
to show the importance of each of these factors.
Score each choice for each factor using numbers from 0
(poor) to 3 (very good). Multiply each score by the weight
of the factor, to show its contribution to the overall
selection.
Finally add up the total scores for each option. Select
the highest scoring option.
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