  A number of correlations between observables have been found to exist for
gamma-ray burst (GRB) afterglows, linking ejecta energy to prompt and afterglow
energy release and linking early stage optical and X-ray luminosity to the end
times of these stages. Here, these correlations are compared to thick and thin
shell models for GRB afterglows. In the thick shell model, the time evolution
of the underlying relativistic blast wave is still influenced by the original
ejecta, while in the thin shell model most energy in the explosion has been
transferred to the external medium. It is shown here that the observed
correlations rule out basic thin shell models but not the basic thick shell
model. In the thick shell case, both forward shock and reverse shock dominated
outflows are shown to be consistent with the correlations, using randomly
generated samples of thick shell model afterglows.
