Really interesting article.
Interesting how the author recounts that there was no real lobbying going on until the 1970's.
Also this introduction to the article is very informative:
"Gilens and Page tested those theories by tracking how well the preferences of various groups predicted the way that Congress and the executive branch would act on 1,779 policy issues over a span of two decades. The results were shocking. Economic elites and narrow interest groups were very influential: They succeeded in getting their favored policies adopted about half of the time, and in stopping legislation to which they were opposed nearly all of the time. Mass-based interest groups, meanwhile, had little effect on public policy. As for the views of ordinary citizens, they had virtually no independent effect at all. “When the preferences of economic elites and the stands of organized interest groups are controlled for, the preferences of the average American appear to have only a minuscule, near-zero, statistically non-significant impact upon public policy,” Gilens and Page wrote."