We investigate the inflationary implications of extensions of Poincaré symmetry .
The simplest constructions with local scale invariance lead to universal predictions : the spectral index is n _ { s } = 1 - 2 / N , in excellent agreement with Planck data , while the tensor-to-scalar ratio is determined by a free parameter to r = 12 \alpha / N ^ { 2 } .
For the special value \alpha = 1 one finds symmetry enhancement to the full conformal group .
We show that these findings hold both for two-derivative scalar-tensor theories as well as higher-derivative gravity .
Therefore scale invariance underlies a promising set of inflationary models .