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The rebirth of the 4th Down Bot—A retrospective of football’s grittiest down

A definitive analysis of Chargers’ effectiveness on 4th downs—a multi-part series. 2016 reviewed here.

If you are already familiar with the 4th Down Bot and its methodology, feel free to scroll to the bottom to check out how the Chargers fared on 4th Down in the past. Years 2017 and 2018 will follow shortly!


It wasn’t long ago that the area of Southern California was covered in a dark and dreary funk. It wasn’t necessarily smog, and it wasn’t necessarily unavoidable. San Diego was covered in the self-inflicted agony of gutless play-calling. The stench was everywhere.

The best way to gauge a coach’s fortitude is to see just exactly how they lead their troops on fourth down. The safe play is very rarely the correct play for a team that has crunched the numbers and wants that extra edge that cowardice abhors. It’s easier to blame or congratulate a kicker than it is to make the call that keeps them on the bench for another play.

Out of the darkness, something lurked

Until recently, the perceived bias of wanting to ‘go for it’ in 4th and 1 situations was chalked up to fan pandering. While the NFL is often slow to adopt new schemes and ideas, the utilization of 4th down opportunities has been limited to field goals, punts, and go-for-it plays late in the 4th quarter when necessary.

Then someone crunched the numbers. That beacon in the darkness, of all unexpected entities, happened to be the New York Times. Through tireless work, they constructed a new life form—equal parts monster and saint. This new entity became known as the 4th Down Bot. It was originally designed to analyze the Jets, and it did that with ruthless efficiency. The rest of the league soon fell inside its cross hairs.

The 4th Down Bot was originally built by the New York Times. By 2016, however, the end was near.

The robot methodically crunched all historical precedent and divided every fourth-down play into the same three previous choices, based entirely on the potential for highest return on each attempt. It isn’t a simple game of putting points on the board instead of punting—field goals are only worth taking when your fourth down conversion has less than a 50% chance of succeeding. The entire mainframe of this monster is set on maximizing potential points, and it wants 7 or more every drive. The only time it deviates from this prime directive is when aggression would rather increase the likelihood of the enemy team putting points on the board.

But in 2016, the First Down Bot abruptly stopped live analysis. In 2017, the Bot stopped communications with the human world altogether. Although no historical record indicates why, the prevailing thought is that the Bot had achieved its purpose: to convince people that there was more to 4th Downs than punting. The league seemed all-too-eager to forget the Bot and return to the status quo.

Then the Chargers did something that no one expected

The Chargers put the Mike McCoy years behind them and brought in Anthony Lynn, a relatively untested offensive mind from the middling Buffalo Bills. The culture difference was immediately perceived in press conferences. The results on the field were sorely tested in 2017, with the team going 0-4 to begin the Lynn regime. To his credit, coach Lynn stood his ground and pressed the team even harder. They rallied and made an incredible push to finish the year just outside of the playoffs.

Anthony Lynn had the exuberance and shiny ideals of a promising new coach in 2017, but challenges would rear their head very quickly

2018 was the culmination of Lynn’s work: a team that could be feared on both sides of the ball. He had preached analytics, and he had, presumably, canceled the apocalypse of mediocrity. With the death of the 4th Down Bot, the public could only wonder if this turn-around was due to player skill, better analytics, or dumb luck.

2018 was a grizzly affair that showed that the Chargers team was built to grind.

Rebirth of the 4th Down Bot

The rusting hulk of the 4th Down Bot lied in the wastes of the New York sewer. An insane professor, a failure in all things except quitting, decided that he could rebuild it. Perhaps make it stronger, faster, and in every way more powerful. Professor Fusion, nicknamed Killswitch, decided that the time was right to resurrect the 4th Down Bot. He had the metal scraps shipped to his laboratory in Southern California and got to work.

Labeled a villain by the powers of the NFL, Professor Killswitch is driven by a thirst for a more rational world... at any cost.

In the end, Professor Killswitch was hardly able to improve on the original robot, beyond a few cosmetic upgrades and deactivating its Twitter credentials. Most crucially, 4th Down Bot 2.0 is just as aggressive as its earlier self, but now with more awareness of clock management. This is a robot based on objectivity, and time is simple enough to plug into that: if ‘going for it’ increases your odds of winning OR if the likelihood of another drive diminishes with turning the ball over, recommendations could change. This change puts the new Bot closer to reality, but a third dimension (time/urgency) is harder to add to a 2-dimensional poster. In any event, now the 4th Down Bot is alive again and he’s set his sights on LA.

The 4th Down Bot 2.0 is similar to its predecessor, but with better play calling in do-or-die drives.

Mission and Purpose

It is important to remember that the 4th Down Bot is neither good nor evil. Its ruthless power is in analytics, but even positive analytics are just dice that favor higher numbers 50.1% of the time or more.

The 4th Down Bot 1.0 or 2.0 does not take into account individual player or team strengths, but bases its recommendations entirely on a melting pot of historical proof. In fact, both versions of the Bot are identical, except that 2.0 is more aggressive near the end of quarters 2 and 4. Within 3 minutes and 45 seconds of the end of either half, the Bot 2.0 adds a new wrinkle to the priority algorithm: Winning point margin > Keep drive alive > Preserve field position.

Comparing what coaches SHOULD do with what they OFTEN do provides interesting insights

A Nice, Warm Benchmark

In the next episodes of this series, we will compare the Chargers’ 2018 season to 2017 and 2016 to give an accurate benchmark for comparison. The purpose of this exercise, other than showing science running amok, is to tell whether Anthony Lynn is improving on the previous regime or if 2018 really was just a lucky, statistically irrelevant year.

Without further adieu, here’s how Mike McCoy fared in his last year.


Sun, Sep 11 @ Chiefs (LOSS)

STAT TOTALS: 5/8 (62.5% agreement)

Note: 2 of 3 Field Goal plays agreed with ‘Bot, one Field Goal-miss disagreed (should have run the ball).

Sun, Sep 18 Vs. Jaguars (WIN)

STAT TOTALS: 5/5 (100% agreement)

Note: 1 of 1 scoring Field Goal success was agreed.

Sun, Sep 25 @ Colts (LOSS)

STAT TOTALS: 4/6 (66.6% agreement)

Note: 2 of 3 Field Goal-attempt plays agreed with ‘Bot, one Field Goal-success disagreed (should have run the ball).

Sun, Oct 2 Vs. Saints (LOSS)

STAT TOTALS: 5/7 (71.4% agreement)

Note: 2 of 2 scoring-attempt plays agreed with ‘Bot. Both scored.

Sun, Oct 9 @Raiders (LOSS)

STAT TOTALS: 1/3 (33.3% agreement)

Note: Neither Field Goal attempt should have been attempted. The second attempt resulted in a fumble recovery.

Thu, Oct 13 Vs. Broncos (WIN)

STAT TOTALS: 5/10 (50.0% agreement)

Note: 3 of 4 Field Goal attempts agreed. One conversion run was agreed. All attempted field goals and conversions were successful.

Sun, Oct 23 @Falcons (WIN)

STAT TOTALS: 5/6 (83.3% agreement)

Note: 2 of 3 Field Goal-attempt plays agreed with ‘Bot, one passing play conversion was agreed (and successful).

Sun, Oct 30 @Broncos (LOSS)

STAT TOTALS: 8/9 (88.8% agreement)

Note: 1 Field Goal attempt (successful) agree; 2 passes (both incomplete) agreed.

Sun, Nov 6 Vs. Titans (WIN)

STAT TOTALS: 3/6 (50.0% agreement)

Note: 2 of 3 Field Goal attempts agreed (all successful).

Sun, Nov 13 Vs. Dolphins (LOSS)

STAT TOTALS: 5/5 (100.0% agreement)

Note: 1 of 1 Field Goal attempt agreed and was successful. An agreed punt resulted in a muffed catch recovered by Chargers.

Sun, Nov 27 @Texans (WIN)

STAT TOTALS: 4/6 (66.6% agreement)

Note: No field goal attempts made; none recommended. One agreed punt resulted in a fumble.

Sun, Dec 4 Vs. Buccaneers (LOSS)

STAT TOTALS: 4/4 (100.0% agreement)

Note: 1 of 1 Field Goal attempt agreed, but was unsuccessful.

Sun, Dec 11 @Panthers (LOSS)

STAT TOTALS: 4/5 (80.0% agreement)

Note: 1 Field Goal attempt (successful) agreed, but one pass (should be a punt) was intercepted deep in Chargers territory.

Sun, Dec 18 Vs. Raiders (LOSS)

STAT TOTALS: 5/7 (71.4% agreement)

Note: 1 Field Goal attempt (successful) agreed, but one pass (should be a punt) was intercepted deep in Chargers territory.

Sat, Dec 24 @Browns (LOSS)

STAT TOTALS: 6/9 (66.6% agreement)

Note: 2 of 3 attempted Field Goals agreed (one made, one blocked, one missed), and one run conversion agreed.

Sun, Jan 1 Vs. Chiefs (LOSS)

STAT TOTALS: 3/4 (75.0% agreement)

Note: 2 of 2 Field Goals (successful) and one run conversion agreed.

2016 Total agreement: 72/100 (72.0% agreement)

Average NFL coach agreement: 78/100 (78% agreement)

2016 4th Down Conversions made: 6 of 12 (50% success)

So what does all of this mean??

Mike McCoy is often vilified for his playcalling. His tenure in San Diego left much to be desired for most fans, and one of the biggest reasons was that his team seemed to play “not to lose” instead of playing to win. After crunching the numbers, we could harp on McCoy for his relatively conservative offense. He was less ‘gutsy’ than the average NFL coach, and the season’s large number of close losses could have been improved with just a handful of different decisions each week. HOWEVER- there are two important facts to consider before dropping the guillotine on McCoy’s legacy. First--while he disagreed with 4th down statistics more often than 23 of NFL coaches, that’s not a terribly significant difference. We’re talking about, at best, 10 plays that could’ve been differently managed to bring him back in line with the average. Second—after seeing the totals for successful conversions (50%), the odds really weren’t on his particular team’s side, regardless of the statistics for the rest of the NFL. A conversion’s success was, at best, a coin flip in 2016.


Coach Anthony Lynn takes on the 4th Down Bot 2.0. It is a winner-take-all bout, with the future of the franchise at stake. Was 2018 an aberration? Tune in next time to find out!

-Goro “Calculator Envy 2.0” Saurus