There are many methods available for sampling spray drift, and a great variety of estimates of spray drift have been published. Available data on spray drift were collected from different studies and the measurements of spray drift were analysed to determine similarities and differences between the individual studies. Each of the methods varied significantly in their estimates of spray drift. This variation was due to many factors that differed between the published sources, such as environmental conditions, cropping system, equipment used and the tracer used. It is suggested that in order to compare drift measurements between published studies, measurement techniques and sampling distances must be standardised, and environmental conditions (humidity and temperature) should be restricted to within certain boundaries in the field, and controlled within artificial tests, unless, of course, the effect of this variable on drift is being examined.