In this work, we report on a study carried out to identify
a set of metrics to early estimate the development effort of
mobile apps. The applied methodology was inspired by the
work of Mendes et al. who addressed a similar problem in
the field of web applications. In particular, we extracted an
initial set of metrics by analyzing the online quotes forms
that companies made available on their websites. Afterward,
a Delphi approach with four project managers was employed
to identify the proposed set of 41 relevant factors.