The phenomenon of irradiation creep in graphite is essential to the design and construction of graphite-moderated reactors. Recent experimental results have shown large apparent reductions in creep rate for creep strains greater than +/- 1%. It is shown that this is not a true reduction in creep rate, but is an artifact resulting from changes in the properties of the stressed samples, which modify their dimensional changes under irradiation compared to the unstressed control samples, and this is not accounted for in the standard definition of creep strain.