On the Hockey Hall of Fame citation for George McNamara, it is noted that he and his brother Howard were known as the "Dynamite Twins" during their playing days. They weren't really twins, but if the moniker measured their playing ability, then why isn't Howard also in the Hall of Fame?
The tale of the tape:
* George, a defenceman, had 39 goals and 13 assists over 8 seasons or 138 games (excluding exhibition game totals and his 2 goals in 3 playoff games). That's 0.28 goals per game or 0.38 points per game.
* Howard, also a defenceman, had 47 goals and 17 assists over 11 seasons or 134 games (excluding exhibition game totals and he had no playoff points). That's 0.35 goals per game, or 0.48 points per game.
Since the two often played on the same team, in the same league, and with a similar style, these statistics are probably comparable. If so, the advantage goes to Howard.
Howard was also known for his size (6 feet, 240 lbs - which was HUGE in that era) and for obvious reasons, dominated opponents physically. No evidence on George's dimensions.
Both won the Stanley Cup, but with different teams.
Not much to choose from it seems, so why is only one twin the Hall?
Here's a possible explanation from Frank Selke Sr., who was on the Hall of Fame nominating committee. In a letter to Mike Rodden, sportswriter and former NHL referee, Selke wrote:
"Between ourselves Mike - when George was admitted [to the Hall] Howard's wife told a friend of mine that George could not carry Howard's skates. I asked [Art] Ross and Lester [Patrick] about this and they said, which one was Howard?"