Relative advantage is exactly what it says: users have to see that an innovation will bring clear improvements over existing practice. This is always a tricky one with innovations in learning since gains in learning are rarely quick or immediate; rather, when used over time, successful innovations lead to effective learning. Relative advantage requires persistent use and its manifestation may be subtle and hard to measure.
Compatibility requires an innovation to be consistent with existing values, experiences or needs. This can also be difficult for ICT. For example, when the focus shifts from teacher to learner, teachers move from expert to learning guide and learners must take responsibility for their own learning.
Successful innovations, says Rogers, are the ones that are easy to understand and use. Everyone who promotes ICT in education should regularly have to adopt a new operating system or program with little or no technical help just to be reminded that technology is still not easy to use nor reliable. Of course, this is changing, but I see enough problems to suggest ICT is still far from simple; too much teacher-pupil talk in some lessons is about the technology not the learning.
Trialability relates to the degree to which the innovation can be tested and experimented with. Personal users tend to do this in private and gain confidence by doing so. Innovations in teaching take place in public and in front of a very critical audience. Moreover, most teachers feel constrained by time, with a lot of material to be covered in a limited period. This does not make experimentation all that attractive.
Observability - the advantages of an innovation must be clear to others and the clearest demonstration of advantage in schools relates to test scores.
Here, evidence is hard to find, as study after study reveals. There is still a question as to whether this is due to a mismatch of outcomes between ICT use for learning and the learning reflected in test results, or that levels of use are too low for its results to be appreciated.
If Rogers is right, it seems we should not be surprised that ICT has not always succeeded in classrooms. However, his model provides pointers for those who design content and are involved in continuing professional development and policy.
When seeking to change practice, we should consider the extent to which an innovation meets Rogers' conditions. Are the advantages clear and made explicit to teacher and learner? Is the school happy to embrace the value system of the innovation? Is it simple to use and reliable? Can it be tested by teachers and learners in a small way and if not how will it be phased in? And will all stakeholders see clear gains?
The education system is able to undergo systemic change and we know how to bring that about - consider the literacy hour. But the models of ICT in teaching have not met Rogers' criteria and this is perhaps why they have yet to succeed.
Angela McFarlane is professor of education and director of learning technology at the Graduate School of Education at the University of Bristol