The ranking of a series of items by means of a series of comparisons between all possible pairs of items.
In all areas of industry and commerce, measurement is the vital essence of decision-making. One of the great obstacles to what may be called ‘scientific’ or ‘systematic’ or ‘reasoned’ decision-making has been the impossibility, or at least the considerable difficulty of measuring many of the decision variables. ‘Paired Comparisons’ is a very simple mathematical technique which enters this problem area and enables some quite intractable variables to be adequately assessed. The particular strength of the technique lies in its ability to put a complex set of items in order according to any desired criterion.
Paired comparisons are of potential use to an office manager if he has to make a decision from a moderate number of alternatives (say 3 to 10). The situation will be such that it is impossible or impracticable to measure the total value of each alternative, and it is likely that the value of an alternative will result from a complex mixture of many variables. Nevertheless in suitable situations it will be possible for the manager to state an overall preference for one alternative when presented with only two alternatives from which to choose.
Perhaps the most frequent application lies in staff selection. Many managers find it extremely difficult to evaluate the training, experience, qualifications, personality and general suitability of a set of candidates according to a formal assessment scheme, but they can compare when selecting a secretary, Jane with Janet, Janet with Roslyn and Roslyn with Jane. A detailed example of staff selection is given on the next page.
Other possible applications are:
The most common application of paired comparisons is in staff selection. You, as the interviewer, find it extremely difficult to put Arnold, Baker, Green, Howell and Jones and others in a final order of preference but you find it reasonably easy to compare any two. The comparisons are carried out on a matrix and the results are then processed in several simple steps including checks for consistency.
The matrix shown here illustrates how such comparisons are recorded. The paired comparisons technique tells us only the relative order of different alternatives, and tells us nothing of their absolute value. Nor does it give any information about the distance apart of the alternatives e.g. how much value (money, time, convenience, utility, etc) lies between first and second, fourth and eight.
Paired comparisons is a simple and moderately powerful technique which any office manager can use to help him make decisions. Although it has a mathematical basis the mathematics can be ignored with complete safety by users. The procedure is straightforward and unambiguous and can be mastered in no more time than is required to read this article.