Spiral consists in three cycles containing the same exact phases, which progressively broaden and enhance the approach. See here for more information. The approach consists in the following : set up the plat-form (cycle 1), gather criteria to evaluate the well and ill-being in homogenous groups (cycle 2), measurement of the actual well-being using the homogenous groups criteria as reference (cycle 3).

But all phases can be done at the first and the second cycle too.