  In a recent empirical study we found that evaluating abstractions of
Model-Driven Engineering (MDE) is not as straight forward as it might seem. In
this paper, we report on the challenges that we as researchers faced when we
conducted the aforementioned field study. In our study we found that modeling
happens within a complex ecosystem of different people working in different
roles. An empirical evaluation should thus mind the ecosystem, that is, focus
on both technical and human factors. In the following, we present and discuss
five lessons learnt from our recent work.
