Simply stated, according to a new research study, the answer is public relations.
While it may not be 'fair' to compare advertising and public relations, it does look at the fundamental question of how you generate buzz around your production.
Is it more cost-effective (or simply effective) to do it through advertising or through a press release? In this study, they tested an online advertising campaign against a press release and found the bottom line in generating traffic with PR was 21.4 to 56.3 percent cheaper than online advertising.
Score one for Broadway's publicity groups.