By the numbers: What justifies tight end induction to Hall of Fame?

Here's a brief foray into the career statistics of all 8 tight ends currently (as of 5/13/2015) inducted into the Football Hall of Fame:

First and foremost, the number of games and seasons played (ordered by % games missed):

1.  John Mackey played 139 games over 10 seasons (missed 1 game, 0.7%)

2.  Ozzie Newsome played 198 games over 13 seasons (missed 10 games, 4.8%)

3.  Mike Ditka played 158 games over 12 seasons (missed 10 games, 6.00%)

4.  Jackie Smith played 210 games over 16 seasons (missed 14 games, 6.25%)

5.  Charlie Sanders played 128 games of 10 seasons (missed 12 games, 9.2%)

6.  Shannon Sharpe played 204 games over 14 years (missed 20 games, 8.9%)

7.  Dave Casper played 147 games over 11 seasons (missed 21 games, 12.5%)

8.  Kellen Winslow played 109 games over 9 seasons (missed 35 games, 24.3%)

With the exception of Kellen Winslow , it looks like the higher percentage in the latter players might be attributed to the extended season length (extended from 14 to 16 games in 1978), which made a season ending injury more costly.  Also, Mackey's low number might be attributed to the fact that the only game his missed in his 9th season was due to the knee injury that cut his career short.

Related to this, the failure time (consecutive initial games) may also be a useful statistic to examine:

1.  John Mackey missed the last game of his 10th (and final) season (139 games).

2.  Jackie Smith missed the 10th game of his 9th season, (135 games)

3.  Mike Ditka, missed the 9th game of his 7th season (92 consecutive games)

4.  Ozzie Newsome missed the 3rd game of his 5th season (66 games)

5.  Shannon Sharpe missed the 2nd game of his 5th season (65 games)

6.  Charlie Sanders missed game 13 of his 4th season (54 games)

7.  Dave Casper missed the 13th game of his 3rd season (40 games)

8.  Kellen Winslow missed the 9th game of his rookie year (8 games)

Mackey's reputation as a speedster and his ability to make tacklers miss, may help explain his longer streak.  On the other end of the spectrum, Winslow battled through knee injuries his entire career, possibly because he was the largest of the group (6'5", 250 lbs), and may have tried to run through more (and possibly lower) tackles as a result.

And here are their career yardage stats (adjusted for catch number), courtesy of the hall of fame:

1.  Jackie Smith: 7918 yards/480 catches (16.5)

2.  John Mackey: 5236 yards/331 catches (15.8)

3.  Charlie Sanders:  4817 yards/336 catches (14.3)

4.  Dave Casper:  5216 yards/378 catches (13.8)

5.  Mike Ditka: 5812 yards/472 catches (13.6)

6.  Kellen Winslow: 6741 yards/541 catches (12.5)

7.  Shannon Sharpe:  10060 yards/815 catches (12.3)

8.  Ozzie Newsome:  7980 yards/662 catches (12.1)

Again, Mackey has an impressive average, but Jackie Smith actually put up better numbers over the course of the longest career of the bunch.

And here are the numbers of receiving touchdowns, adjusted for catches:

1.  Dave Casper 52 TDs/378 catches (13.8% TD)

2.  John Mackey 38 TDs/331 catches (11.5%)

3.  Kellen Winslow 52 TDs/541 catches (9.6%)

4.  Charlie Sanders 31 TDs/336 catches (9.2%)

5.  Mike Ditka 43 TDS/472 catches (9.1%)

6.  Jackie Smith 40 TDs/480 catches (8.3%)

7.  Shannon Sharpe TDs/815 catches (7.6%)

8.  Ozzie Newsome  47 TDs/662 catches (7.1%)

A final statistic of note might be fumbles, adjusted for number of catches:

1.  Ozzie Newsome  3 fumbles/662 catches (0.5%)

2.  Shannon Sharpe 7 fumbles/815 catches (0.9%)

3.  Charlie Sanders 6 fumbles/336 catches (1.8%)

4.  Dave Casper 7 fumbles/378 catches (1.85%)

5.  Mike Ditka 9 fumbles/472 catches (1.91%)

6.  Kellen Winslow 11 fumbles/541 catches (2.0%)

7.  Jackie Smith 12 fumbles/480 catches (2.5%)

8.  John Mackey 11 fumbles/331 catches (3.3%)

To summarize,  these men tended to have long careers (at least 9 seasons), over which they averaged big gains (range: 12.1-16.5 yards/catch), and caught touchdowns (range: 7.1%-13.8% of catches converted to TD) and protected the ball (range: 0.5%-3.3% fumbles/catches).

It might also be interesting to see how Tony Gonzalez (surely the next tight end inductee) fairs on similar statistics:

Tony Gonzalez:
-Missed 2/272 games over 17 year career (0.08%)
-Missed 1st game of 3rd season (32 straight), but had two 120+ consecutive starts thereafter.
-15,127 yards/1325 catches (11.4 yards/catch)
-111 TDs/1325 catches (8.4% TDs/catch)
-6 fumbles/1325 catches (0.04% fumbles/catch)

The interesting thing about his six fumbles is their distribution over time:  3 in 1998 (sophomore year), 2 in 1999, and 1 in 2006.  So after his 1st three years in the league, he only fumbled once!