Pairwise Comparisons
In the Pairwise Comparisons technique the priorities are decided by comparing the
requirements two and two. To get the correct result, all possible pairs should be compared.
However, this means that in practice there can be a huge number of needed comparisons.
Therefore, approximate priorities can be calculated using an incomplete pairwise
comparisons technique, this is what is done in this program if you choose to stop
before all possible pairs have been compared. Although, you are encouraged to keep in
mind that this may result in some errors in the prioritization.
How to use this window:
When the window is open, the current comparison is shown in the text fields and their
relative importance to each other is set using the radio buttons below.
- First choose which criteria to start prioritizing after by using the combobox
in the upper right corner. This can only be done before the first comparison have
been done.
- To set the relative significance, either double-click a radio button or select a
radio button and press Next. This will bring up the next pair to compare. The more
significant one requirement is, than the other, a radio button further to that
side should be selected. If you hold the mouse over a radio button, an explanation
will be shown.
- You can go back to look at and change previously compared pairs by pressing
the Back button.
- Through the progress bar at the bottom of the window and the information
to the right in the window, you can follow your progress and see how many pairs
you have left, throughout the prioritization.
- You must complete at least the same number of comparisons as the amount of
requirements to be able to get any result at all.
- Under the Options menu, intermediate values can be selected to be shown. These
intermediate values are used when a compromise between two adjacent judgments must
be done.
- Another feature to be found under the Options menu is the possibility to set the
number of paths in the graph to use when calculating priorities with the incomplete
pairwise comparisons (IPC) algorithm. Note: For users unfamiliar with the IPC
algorithm it is recommended not to change these.