perhaps methodology would fit.

More context would be nice. I'm tempted to assume they mean "Verlauf" when they say "Gang", in which case I'd translate it "Course of Experiment" or something similar.

I second dan assuming the notion of 'Verlauf' in 'Gang'. I'd just propose replacing "experiment" by "analysis" or "investigation" depending on the topic

I'd choose "outline". It may contain methodological remarks, but its main function is to give an overview of the contents and state how the author has structured the subject-matter.

thanks for the comments guys; hwever outline is not sufficient. In the "Gang of the Untersuchung" the outline is described but in addition reasons why the particular outline has been chosen need to be given and the focus of the study needs to be stated

Did you ever thought about 'structure of analysis/investigation/survey/study/project'? Might be explain it sufficiently for a scientific paper.