  Background: Classifications in meta-research enable researchers to cope with
an increasing body of scientific knowledge. They provide a framework for, e.g.,
distinguishing methods, reports, reproducibility, and evaluation in a knowledge
field as well as a common terminology. Both eases sharing, understanding and
evolution of knowledge. In software engineering (SE), there are several
classifications that describe the nature of SE research. Regarding the
consolidation of the large body of classified knowledge in SE research, a
generally applicable classification scheme is crucial. Moreover, the
commonalities and differences among different classification schemes have
rarely been studied. Due to the fact that classifications are documented
textual, it is hard to catalog, reuse, and compare them. To the best of our
knowledge, there is no research work so far that addresses documentation and
systematic investigation of classifications in SE meta-research. Objective: We
aim to construct a unified, generally applicable classification scheme for SE
meta-research by collecting and documenting existing classification schemes and
unifying their classes and categories. Method: Our execution plan is divided
into three phases: construction, validation, and evaluation phase. For the
construction phase, we perform a literature review to identify, collect, and
analyze a set of established SE research classifications. In the validation
phase, we analyze individual categories and classes of included papers. We use
quantitative metrics from literature to conduct and assess the unification
process to build a generally applicable classification scheme for SE research.
Lastly, we investigate the applicability of the unified scheme. Therefore, we
perform a workshop session followed by user studies w.r.t. investigations about
reliability, correctness, and ease of use.
