Frank Hobson Consulting

practical human resources support

Job Evaluation - pair comparisons

Pair Comparisons

I have always liked the pair-comparison technique. It is a simple way to produce a ranked list that has an application in a wide range of circumstances. Having recently come across an organisation that successfully uses this as the basis of its Job Evaluation (JE) methodology, I thought I might review the technique.

Pair comparison exercises involve taking each item in a list and comparing it, one by one with every other item and awarding a score of, typically, 2, 1 or 0 according to whether the item is bigger, about the same or smaller than the other. When you have compared item one with all the others you repeat the process for item two, and so on. The total points scored by each item gives a ranking order and the extent to which there is bunching and gaps in the score list helps identify break points such as grade boundaries. This is not as tedious as it seems. Firstly, you would not use this for a list of more than 20 to 25 items, but that is a typical size for a list of benchmark jobs in any JE exercises. Secondly, every comparison (A against B) determines the reverse comparison (B against A) so only half the possible number of comparisons need be made. A spreadsheet can take care of these reverse calculations and the final addition (see diagram below). Not all comparisons need much thought. For example, it does not take long to decide whether Chief Executive is a bigger job than Receptionist. An added advantage is that the team making the comparisons do not have to be in the same room every time.

As a job evaluation methodology whole job comparisons can be seen as old hat, and possibly open to challenge. However, many organisations nowadays are adopting a job family approach with relatively few bands in each family. In such cases sophisticated JE methodologies often produce a false level of discrimination that then has to be de-tuned to give a workable result. You can enhance the pair comparison technique by comparing jobs on a factor basis and totalling the scores for each factor.

The other traditional grading-related application of the technique is in deriving a felt-fair ranking list of benchmark posts - either as the first stage of a JE exercise or as an analytical tool to help decide whether your current scheme is really as out-of-line as your managers are telling you.

With a bit of tweaking I have also used the technique to agree the number of grades that are needed in a pay structure.

But why stop there? Can't decide where to go for your holiday? Draw one up for the family to complete. Benidorm vs Butlins - score 2, 1 or 0? Wedding invitations getting out of hand? List all your friends and relations, score them and see who not to invite.

Frank Hobson

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