Opendota only gets MMR from people who show their MMR on their profile . It ' s way more likely that lower skilled players won ' t show it on their profile . They still use my MMR from may because I ' ve got exposed data on , but removed it from my profile around that time . 1 , 6 M is also a relatively small userbase and is more likely to include people who care about their mmr ~ higher mmr players . Also , the leaderboards show like the . 001 % top 200 so even a 5 k player is basically god tier in relative terms . Slacks is 5 k because he plays a lot of dota and is good at it . The pre release distributions released by Valve should still in theory be more accurate since the only new MMR is from new accounts and new accounts shouldn ' t calibrate at higher mmrs .