A statistical analysis was published with the rankings of the five greatest rugby players of all time on British website ruck.co.uk.
Of Carter, the study said, "The greatest back of the professional era, his record speaks for itself.
"Way out in front as the leading points scorer in international rugby history, with 1598 points from his 112 caps. Throw in a further 1708 points for the Crusaders and the fly-half's impact on the game cannot be emphasised enough."
And of McCaw, the group said, "Complementing his natural prowess over the ball, McCaw worked and worked at his game, adding handling skills and dynamic running to turn himself into the complete openside.
"Unflinchingly brave, he has remained a quite outstanding exponent at the breakdown throughout his career, while also possessing the athleticism and footballing ability to serve as the classic link man and the ball-carrying dynamism to consistently break the line. He had the lot."
Former Ireland and British & Irish Lions centre and captain Brian O'Driscoll came in third with his record 26 tries in Six Nations rugby and his choice in 2006, 07 and 09 as the player of the tournament. He led Ireland to one Grand Slam and three Triple Crowns.
Australian wing-fullback David Campese was ranked No4. Still second on the Test try-scoring list with 64 tries and was a Test centurion for Australia.
Former England lock and World Cup-winning captain in 2003 Martin Johnson was ranked No5.
The basis of the comparisons was each player was ranked on total Test wins, Test win percentages, tries scored, domestic trophies and international trophies.