Trend analysis on the metadata of program comprehension papers As program comprehension is a vast research area, it is necessary to get an overview of its rising and falling trends. We performed an n-gram frequency analysis on titles, abstracts and keywords of 1885 articles about program comprehension from the years 2000-2014. According to this analysis, the most rising trends are feature location and open source systems, the most falling ones are program slicing and legacy systems.