Sports Illustrated uses statistics to project 47 wins for Celtics

You can't argue with math.

Projecting the NBA standings for the 2015-16 season by Win Shares - NBA - SI.com

Boston Celtics 2014-15 record (win shares): 40-42 (41.0)
Key players gained: Amir Johnson (5.1), David Lee (3.2), full seasons of Isaiah Thomas (+4.0) and Jonas Jerebko (+1.9)
Key players lost: Brandon Bass (5.3), Jeff Green (2.0)
Projected 2015-16 win shares (record): 47.4 (47-35)

The rebuilding job at the Garden continues to zoom along without a hitch. The Celtics will be a ton of fun to watch in 2015-16, and should expect to improve on their playoff seeding from last season. Acquiring Lee gives Boston some much-needed scoring down low, as well as a respected, team-first veteran with championship experience. And it’s somewhat of a miracle that Danny Ainge was able to convince Johnson to sign for two years and $16 million after the power forward had earned himself a more ludicrous deal in Toronto.

Obviously nobody can predict the future accurately and all stats have their flaws.

Of course, a player's 2014-15 Win Shares is somewhat reliant upon the quality of the teams he played for. And from season to season, the statistic can be affected by a number of factors—how a player fits into their team's offensive and defensive systems, any change in minutes per game, young players getting better and old players getting worse, etc.

Still, it is nice to see that at least one metric has this team pointed upward in their progression.

Note: Perhaps not a good sign for their math skills, the SI author seems to have gotten Amir Johnson's salary figures wrong.  He signed for 2 years at $12M per year with the 2nd year being a team option.  That adds up to $24M potential salary, not $16M.