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