Cosmic Confusion and Structure Formation

We present a re-analysis of the cosmic confusion hypothesis, elucidating the degree to which ``confusion’’ can be expected to hold in a class of flat, adiabatic models. This allows us to devise a simple and accurate fitting function for the height of the first peak in the radiation power spectrum in a wide range of inflationary inspired models. The range preferred by current data is given, together with a discussion of the impact of measurements of the peak height on constraining models of structure formation.