Various efforts have been conducted since the 1970s to empirically examine the TRPF. Studies supporting or arguing in favour of it include those by Michael Roberts, Minqi Li, and Deenpankar Basu (2012). Studies critical or contradicting the TRPF include those by Themistoklis Kalogerakos, Òscar Jordà and Simcha Barkai. Other studies, such as those by Basu (2013), Elveren and Ivan Trofimov, report mixed results or argue that the answer is not yet certain due to conflicting findings and issues with appropriately measuring the TRPF.