Intermediate inflation in light of the three-year WMAP observations

The three-year observations from the Wilkinson Microwave Anisotropy Probe have been hailed as giving the first clear indication of a spectral index nₛ<1. We point out that the data are equally well explained by retaining the assumption nₛ=1 and allowing the tensor-to-scalar ratio r to be nonzero. The combination nₛ=1 and $r>0$ is given (within the slow-roll approximation) by a version of the intermediate inflation model with expansion rate H(t)∝t^-1/3. We assess the status of this model in light of the WMAP3 data.