On 2014 Dec 13, David Keller commented:

The grandfathered internists had 20% more experience in practice than the MOC'ed internists

The "grandfathered" internists in this study were certified in 1989, while the "MOC'ed" internists (those forced to undergo Maintenance of Certification) were certified in 1991. The study was conducted in 2001, so the grandfathered internists had 12 years in practice, while the MOC'ed internists had only 10 years in practice. The difference of 20 percent more practice experience could account for much of the difference between the two groups; for example, the fact that the more experienced internists spent more money on patient care might reflect their increased experience in billing Medicare and insurance companies, which is knowledge not taught during the MOC process; rather, skill at billing is acquired through years in practice.

On 2014 Dec 13, David Keller commented:

The grandfathered internists had 20% more experience in practice than the MOC'ed internists

The "grandfathered" internists in this study were certified in 1989, while the "MOC'ed" internists (those forced to undergo Maintenance of Certification) were certified in 1991. The study was conducted in 2001, so the grandfathered internists had 12 years in practice, while the MOC'ed internists had only 10 years in practice. The difference of 20 percent more practice experience could account for much of the difference between the two groups; for example, the fact that the more experienced internists spent more money on patient care might reflect their increased experience in billing Medicare and insurance companies, which is knowledge not taught during the MOC process; rather, skill at billing is acquired through years in practice.