IMS Learning Design (LD) is the only available interoperability specification in the area of technology enhanced learning that allows the definition and orchestration of complex activity flows and resource environments in a multirole setting. IMS LD has been available since 2003, and yet it has not been widely adopted either by practitioners or by institutions. Much current IMS LD research seems to accept the assumption that a key barrier to adoption is the specification's conceptual complexity impeding the authoring process. This paper presents an empirical study to test this assumption. Study participants were asked to transform a given textual design description into an IMS LD unit of learning using 1) paper snippets representing IMS LD elements and 2) authoring software. The results show that teachers with little or no previous IMS LD knowledge were able to solve a design task that required the use of all IMS LD elements at levels A and B. An additional finding is that the authoring software did not facilitate people in producing better solutions than those who used paper snippets. This evidence suggests that conceptual complexity does not impede effective IMS LD authoring, so the barriers to adoption appear to lie elsewhere. (Contains 8 figures and 4 footnotes.)