  Best-fit values of the spectral index of the curvature perturbation are
presented, assuming the $\Lambda$CDM cosmology. Apart from the spectral index,
the parameters are the Hubble parameter, the total matter density and the
baryon density. The data points are intended to represent all measurements
which are likely to significantly affect the result. The cosmic microwave
anisotropy is represented by the COBE normalization, and heights of the first
and second peaks given by the latest Boomerang and Maxima data. The slope of
the galaxy correlation function and the matter density contrast on the
$8h^{-1}\Mpc$ scale are each represented by a data point, as are the expected
values of the Hubble parameter and matter density.
  The `low-deuterium' nucleosynthesis value of the baryon density provides a
final data point, the fit giving a value about one standard deviation higher.
The reionization epoch is calculated from the model by assuming that it
corresponds to the collapse of a fraction $f\gsim 10^{-4}$ of matter.
  We consider the case of a scale-independent spectral index, and also the
scale-dependent spectral index predicted by running mass models of inflation.
In the former case, the result is compared with the prediction of models of
inflation based on effective field theory, in which the field value is small on
the Planck scale. Detailed comparison is made with other fits, and other
approaches to the comparison with theory.
