Thanks for your question. While the identity of Hjort must remain a mystery perhaps I should give a little more information why I do this.
One of the main motivations was my own search for schools. I was disappointed by the lack of quality information that was available and the lack of unbiased sources. There seemed to be two camps out there
1) The Princeton MBA crowd (people who didn't really know what programs schools actually offer, they just the name sounds impressive to strangers and grandparents)
and
2) The "it doesn't really matter where you go" crowd who lumped all schools together as being about the same despite vast differences in quality and opportunity
My own experience ignited a desire to investigate further. I soon realized that there are vast differences in quality but that schools of similar quality/reputation tend to cluster together. Instead of spending time worrying about whether a given program was "really" number 10 or number 12 candidates could focus on identifying programs of similar quality that offered the right "fit" for them
My main goal is to help point GMAT Club members in the right direction for whatever they are seeking. While I have strong credentials, I choose not to rely on them in this context. I want candidates to perform their own due diligence and investigate further rather than believe something just because I (or some other consultant)say so.