SMCE window

Weigh - Pairwise Comparison   

 

 

Assign weights to multiple factors and optional groups that occur under the selected main goal, or to multiple factors and optional groups that occur under the selected sub goal.

In the pairwise comparison method, also known as the Analytical Hierarchy Process (AHP) (Saaty), you must indicate for each pair of factors which factor is the most important one. Subsequently you must indicate in qualitative terms to what extent a factor is more important than another. The pairwise comparison method converts these comparisons of all pairs of factors to quantitative weights for all factors.

For more information, see also Weigh methods (additional info), section Pairwise comparison.

The dialog box is a kind of wizard and consists of two sheets.

Pairwise Comparison sheet

Dialog box options:

Current comparison column:

 

This column each time shows two factors that are to be compared. For each pair of factors, you must indicate which factor is the more important than the other; in other words, you must indicate in qualitative terms, using Saaty weights, to what extent one factor is more important than the other.

Assigning Saaty weights can be done:

  • by selecting the correct wording in the drop-down list box, or
  • by dragging the slider up or down until the correct wording is visible in the drop-down list box.

Comparisons column:

 

This column lists all unique pairs of factors that need to be compared to each other.

When a check box is selected, this pair of factors has already been compared to each other.

When a check box is not yet selected, that pair of factors still needs to be compared.

The application keeps track of whether factors have been compared to each other or not.

The selected option button shows you the currently selected pair of factors that is to be compared. To store Saaty weights for the currently selected pair and move to a next pair: click the Next button.

Next

Press the Next button to select the next pair of factors. When all pairwise comparisons are done, the Next button will lead to the sheet with the Pairwise Comparison - Results.

Back

Press the Back button to go back to the previously selected pair of factors.

Choose other method

Click the Choose other method button to open the Weights dialog box to choose another Weigh method.

Warning:

Within pairwise comparison, the number of comparisons increases combinatorially with the number of factors (n*(n-1)/2). For example, the assessment of the weights of 4 factors involves no more than 6 comparisons, but assessment of the weights for 10 factors requires as many as 45 comparisons. It is not recommended to use this method if the number of factors is higher than 7 (21 comparisons). The inconsistency ratio is only calculated if the number of factors is 3-9.

Pairwise Comparison - Results sheet

Dialog box options :

Resulting Normalized Weights column:

 

All factors are listed with their resulting normalized weights. The sum of all resulting normalized weights is always 1.

Inconsistency ratio:

An index between 0 en 1 that indicates whether the pairwise comparisons are sufficiently consistent. A value of 0 indicates complete consistency; a value larger than 0.1 indicates inconsistency.

Back

Press the Back button to go back to the Pairwise Comparison sheet to assign other Saaty weights to one or more pairs of factors.

Finish

Press the Finish button to close the Pairwise Comparison dialog box and finish weighing.

Choose other method

Click the Choose other method button to open the Weigh dialog box to choose another Weigh method.

Note:

After weights have been assigned, the criteria tree viewer will show the following:

 

  Main goal or sub goal--Pairwise
     0.21 Criterion name--Std:...
     0.42 Criterion name--Std:...
     0.31 Criterion name--Std:...
     0.06 Criterion name--Std:...
Pair-wise comparison: all factors are considered, but the user needs to specify for each pair of factors considered which of these two factors is more important or less important than the other; the specification of the importance of factors is done in fixed phrases or with a slide bar.

Reference:

See also: