  Reconstructing the shape of the primordial power spectrum in a model
independent way from cosmological data is a useful consistency check on what is
usually assumed regarding early universe physics. It is also our primary window
to unknown physics during the inflationary era. Using a power-law form for the
primordial power spectrum $P_{in}(k)$ and constraining the scalar spectral
index and its running, \cite{Peiris03} found that the first year WMAP data seem
to indicate a preferred scale in $P_{in}(k)$. We use two complementary methods:
the wavelet band powers method of \cite{pia1}, and the top-hat binning method
of \cite{Wang99} to reconstruct $P_{in}(k)$ as a free function from CMB data
alone (WMAP, CBI, and ACBAR), or from CMB data together with large scale
structure data (2dFGRS and PCSZ). The shape of the reconstructed $P_{in}(k)$ is
consistent with scale-invariance, although it allows some indication of a
preferred scale at $k \sim 0.01$Mpc$^{-1}$. While consistent with the possible
evidence for a running of the scalar spectral index found by the WMAP team, our
results highlight the need of more stringent and independent constraints on
cosmological parameters (the Hubble constant in particular) in order to more
definitively constrain deviations of $P_{in}(k)$ from scale-invariance without
making assumptions about the inflationary model.
