  Internal software quality determines the maintainability of the software
product and influences the quality in use. There is a plethora of metrics which
purport to measure the internal quality of software, and these metrics are
offered by static software analysis tools. To date, a number of reports have
assessed the validity of these metrics. No data are available, however, on
whether metrics offered by the tools are somehow validated in scientific
studies. The current study covers this gap by providing data on which tools and
how many validated metrics are provided. The results show that a range of
metrics that the tools provided do not seem to be validated in the literature
and that only a small percentage of metrics are validated in the provided
tools.
