Moss et. al. (2007) performed a very substantial study on the impact of the widespread introduction of IWBs in London schools. This is the only study I have seen that addresses learning outcomes. Over several years, they tracked surveys aimed at revealing student motivation in addition to student performance via test scores. They also recorded a large quantity of teaching sessions with the IWBs and used them to report on the type of pedagogies being used by teachers.
They did find an increase in student motivation when IWBs were first introduced, which quickly faded with time. More interestingly, they found only one instance of a positive effect on test scores year to year, in English classes. Embarrassingly, negative effects were found several times in mathematics and science classrooms. None of the effects were statistically significant. Oops!
This study suffers from the usual problems to do with self-reporting of student motivation levels. The statistical analysis of student test scores, however, appears to be by design, fairly sound. This is essentially because they tracked the same teachers through the transition phase of introducing IWBs. Thus for the most part, they were able to cleanly isolate the IWBs as the primary change in the classrooms over this period. I would have obviously liked to have seen a control group used. There is the chance that other system wide changes to school policies may have affected the outcomes. This wasn’t discussed in the study, however, so it is difficult to know. The effectiveness of the testing practices for measuring student learning outcomes is certainly up for debate as well.
Moss, G; Jewitt, C, Levaaic, R; Armstrong, V; Cardini, A and Castle, F (2007) The interactive whiteboards, pedagogy and pupil performance evaluation: an evaluation of the Schools Whiteboard Expansion (SWE) Project: London Challenge. DfES Research Report 816 (London, DfES).