Although the early modern period was marked by increasing legislative concern with the standardisation of weights and measures, this was a process which made only gradual headway prior to the nineteenth century. With a plethora of local weights and measures standing alongside the still evolving national standards, identifying which particular system of weight or measurement was in use in various contexts has posed one of the most intractable evidential problems we have had to face. Zupko's paper on weights and measures in Scotland makes clear how complex the situation could be. In Forfarshire, to take one example, butcher meat was sold by Scottish troy weight, but butter and cheese according to a tron pound which varied in size across the county from 22 oz. avoirdupois in Dundee, Arbroath and Cupar to 27 oz. avoirdupois in Kirriemuir. In spite of Zupko's work and the invaluable evidence to be found in John Swinton's late eighteenth-century plea for standardisation, a full understanding of the regional use of customary systems remains elusive.

Interpreting the price series in the foregoing tables is, to some extent confused rather than clarified by the process of standardisation that was underway. Thus whilst many of the longer price series, in particular the fiars, were probably initially set down in terms of local customary measures, in time the national standards came to be adopted.