  In general, professionals still ignore scientific evidence in place of expert
opinions in most of their decision-making. For this reason, it is still common
to see the adoption of new software technologies in the field without any
scientific basis or well-grounded criteria, but on the opinions of experts.
Experimental Software Engineering is of paramount importance to provide the
foundations to understand the limits and applicability of software
technologies. The need to better observe and understand the practice of
Software Engineering leads us to look for alternative experimental approaches
to support our studies. Different research strategies can be used to explore
different Software Engineering practices. Action Research can be seen as one
alternative to intensify the conducting of important experimental studies with
results of great value while investigating the Software Engineering practices
in depth. In this paper, a discussion on the use of Action Research in Software
Engineering is presented. Aiming at better explaining the application of Action
Research, an experimental study (in vivo) on the investigation of the
subjective decisions of software developers, concerned with the refactoring of
source code to improve source code quality in a distributed software
development context is depicted. In addition, some guidance on how to
accomplish an Action Research study in Software Engineering supplement the
discussions.
