Harvard has repeatedly told Landmark to stop using its name.
There is no scientific peer-reviewed and published research that offers any meaningful objective measurement regarding Landmark's supposed results.
Landmark instead relies upon anecdotal stories from its graduates extolling what they say are its "benefits."
Landmark certainly has the money to fund meaningful research to measure the effectiveness of its programs. However, the for-profit privately owned company has chosen not to.
Meanwhile Landmark generates more complaints than any other single group included within this database and they have been repeatedly sued for personal injuries by participants linked to their programs.
As a direct result of those lawsuits Landmark now routinely expects participants to sign a release waiving the right to a trial by jury if they are injured and decide to pursue a claim.
This link explains why "mass marathon training" like Landmark is potentially unsafe.
This link explains coercive persuasion techniques often used by groups like Landmark.