How valid is this research? They seemed to have arbitrarily chosen factors that the researchers seem to feel is "essential to democracy" and then simply decide

How valid is this research? They seemed to have arbitrarily chosen factors that the researchers seem to feel is "essential to democracy" and then simply decide that these factors are in decline. Maybe I missed this but I didn't see the researcher list what the actual factors were that were "essential for democracy" and how these factors were chosen. It seemed as they just arbitrarily picked factors that they felt were essential for a democracy and then showed that these factors were experiencing a decline. The countries chosen in the study, Poland and Venezuela are particularly poor examples as they were both countries that were under long periods or autocratic rule and then briefly attempted a transition to democracy which failed. To hold these up as examples of a general trend of failing democracy seems misleading. What this really seems to me is people with a particular political bias sounding the bell of doom because a candidate they dislike won the election. Really they even mention Trump in the article and mention his election as a sign of failing democracy - you can't get much more biased than that.