On the Use of Unreplicated Pairing in Forestry Planning

Abstract

ABSTRACT The assessment of judgemental information belongs traditionally to a branch of psychology which is known as psychometrics or psychophysics. One of the most well-known psychometric “laws” is Thurstone's Law of Comparative Judgement which is based on the assumption that relative preferences among different criteria (“stimuli”) can be established if the criteria are lined up in pairs. Thurstone was a statistician and his approach requires replicated pairing. Foresters who use replicated pairing correctly assume that there is a population of judgements in a given set of criteria, i.e. that an individual's preferences are usually not consistent. Replicated pairing is, in theory, most desirable, but it can be very time consuming, and is therefore likely to be rejected by management staff. Unreplicated pairing, if used with circumspection and refinement, can be a realistic alternative for obtaining foresters preferences. Examples are presented to demonstrate the method.