The theory of inflation gives certain predictions for the amount of primordial gravitational waves compared to the amount of density perturbations. These predictions are, in principle, verifiable through observation of the Cosmic Microwave Background.
I study theoretical and observational claims made mainly by Leonid Grishchuk concerning the inflationary predictions. A theoretical investigation of his claims and the controversies that followed them is carried out. A replication of data analyses carried out in Zhao et al. (2009) is done with certain improvements, and a direct test of various claims made in that paper concerning the constancy of the spectral index is performed, using 5-year and 7-year WMAP data.
I find Grishchuk's theoretical claims to be in error, and the claims made in Zhao et al. (2009) to not hold up under closer scrutiny.