  Through a homogeneous analysis of spectroscopic literature data of red giant
stars, we determine the radial metallicity profiles of 30 dwarf galaxies in the
Local Group. We explore correlations between the calculated metallicity
gradients and stellar mass, star formation history and environment, delivering
the largest compilation to date of this type. The dwarf galaxies in our sample
mostly show metallicity profiles decreasing with radius, with some exhibiting
rather steep profiles. The derived metallicity gradients as a function of the
half-light radius, $\nabla_{\rm [Fe/H]} (R/R_e)$, show no statistical
differences when compared with the galaxies' morphological type, nor with their
distance from the Milky Way or M31. No correlations are found with either
stellar mass or star formation timescales. In particular, we do not find the
linear relationship between $\nabla_{\rm [Fe/H]} (R/R_e)$ and the galaxies'
median age $t_{50}$, as instead shown in the literature for a set of simulated
systems. The presence of high angular momentum in some of our galaxies does not
seem to have an impact on the gradient values. The strongest gradients in our
sample are observed in systems that are likely to have experienced a past
merger event. By excluding them, the analysed dwarf galaxies show mild
gradients ($\sim -0.1$ dex $R_e^{-1}$) with little scatter between them,
regardless of their stellar mass, dynamical state, and star formation history.
These results are in good agreement with different sets of simulations
presented in the literature and analysed using the same method as for the
observed sample. The interplay between the multitude of factors that could
drive the formation of metallicity gradients in dwarf galaxies likely combine
in complex ways to produce in general comparable values.
