The Los Angeles Chargers have lost 16 of their last 21 games but have also been the victims of comically bad luck.

From bad calls to an unsustainably poor turnover differential and inept special teams play, the franchise has been outside of playoff contention despite generally solid play on offense and defense.

Some of their wounds have also been self-inflicted though, particularly this season, as they are 23rd in both points scored and points allowed.

Their struggle to put up points is surprising given the fact that the Chargers were ninth in scoring last year. Poor starting field position is one culprit -- Los Angeles ranks 5th in yards per drive and 27th in average starting field position, according to Football Outsiders.

They are also not doing themselves any favors with their playcalling, particularly in terms of early pass/run balance. Los Angeles has been one of the NFL's least efficient running teams, coming in at 23rd in yards per carry (3.6). Starting running back Melvin Gordon also ranks 39th out of the 50 running backs with at least 20 carries in Rushing Net Expected Points (NEP) per carry and 41st in Success Rate (the percentage of plays that yield positive NEP).

When putting the ball in the air, L.A. ranks ninth in net yards per drop back and 11th in Adjusted Passing NEP per play, while quarterback Philip Rivers is fourth in Passing Success Rate.

But when we take a look at first downs in the first half -- before the score of the game truly begins to have an impact on play calling -- the Chargers are relying heavily on their ground game and routinely putting Rivers at a disadvantage.

Wasting Early First Downs

At first glance, it does not seem like the Chargers are running too much at all. They have dropped back to pass on 67.5% of plays this season, which is the fourth-highest rate in the league.

However, this overall rate seems to be heavily influenced by game script. In the first half, the Chargers are considerably more run-heavy, throwing just 56.8% of the time, which is below the league average in the first two quarters of 58.1%.

Even this below-average rate is partly an attempt to throw themselves out of the hole they dug themselves in on first down. Only five teams have thrown less frequently on first down in this part of the game than the Chargers, who drop back 38.9% of the time in such situations.

Los Angeles has trailed at halftime in three of their four games, and it is only then that they begin to rely on Rivers and his receivers. In the second half, the Chargers morph into the league's pass-happiest team.

This clearly is not working for the Chargers, who rank 22nd in first-half points per game (9.2) and 13th in first downs per play in the first half. The second mark is still above the league average, but it pales in comparison to last year, when the Chargers ranked fourth in first-down rate in such situations.

The number is also a credit to Rivers and his ability to overcome unfavorable distances to go on second down, though Los Angeles would be better off if he did not have to be in such situations in the first place.

On 1st-and-10, the Chargers are only gaining 2.4 yards per carry, the lowest average in the NFL and 1.8 standard deviations below the mean. In terms of the percentage of first-and-10 rushes that gain at least four yards, the Chargers are again last at 26.7%, which is 2.4 standard deviations below the mean.

As a team, the Chargers' running backs have ran 47 times on first down for -15.93 Rushing NEP (-0.34 per carry) with just a 19.2% Success Rate.

If we only look at 1st-and-10s in the first half -- the spots where the Chargers are the most run-heavy -- the results are not any better. In such situations, they are averaging 2.3 yards per rush while gaining at least four yards 22.6% of the time (both marks rank 31st).

Their collective Rushing NEP per carry is -0.33, and their Success Rate is 18.8% in those situations.

Throwing on First Down

Contrast these marks with those from when the Chargers drop back to pass.

Los Angeles has been around league average in terms of gains on first down passes (ranking 18th with 7.2 yards per drop back), though it has fared worse in terms of gaining at least four yards on these plays (doing so just 49.1% of the time to rank 26th).

On the rare first-down pass in the first half, while the Chargers average gain is greater (8.3, which is eighth-best), they have gained at least four yards less frequently (45.0% of the time, 24th).

Still, even if this does not improve, these outcomes are significantly better than when the Chargers run. Their average first down pass gains exactly three times the yardage of their average first down rush, with a success rate that is nearly twice as high. Passing is just generally a more effective way to move the ball in the NFL.

Also, the Los Angeles passing attack has gotten better after first down, and this has helped the Chargers offense look competent, despite its consistent need to climb out of an early hole.

On second down, they are tied for the fifth-highest first-down rate (36.4%) in the league despite needing an average of 8.7 yards to move the chains, the sixth-most in the league. This success is mostly the result of their passing game, as the Chargers throw on 71.4% of their second downs.

They are eighth (7.2) in yards per drop back and tied for seventh in passing first-down rate (40.0%) on second down.

The Los Angeles running game is also better on second down and has averaged 5.7 yards per carry. Running into softer boxes expecting a pass on second and long probably helps the average, but the Chargers runners are still gaining at least 60% of the yardage required for a first on second down 45% of the time, which ranks 12th in the league, per SharpFootballStats.com. Then again, Los Angeles gains this yardage 55% of the time when they pass on second down, which is third best.

The efficient play on second down has helped, but the first-down disasters have still contributed to Los Angeles facing the 12th-longest average third down, where they have the sixth-lowest conversion rate (34.9%, though note that we are dealing with only a 43-play sample size; last year, the Chargers were 11th in third-down conversion rate).

While regression here will help, the Chargers could also obviously move the chains more effectively by avoiding second-and-long and third-and-long situations altogether. The average team has picked up a first down on second-and-6 or shorter 45.9% of the time, while 3rd-and-6 or shorter yields a first down 53.5% of the time.

The Chargers' problem is that they are in such situations too infrequently, partly because they are repeatedly rushing for minimal gains on first down. This is especially true in the first halves of games.

They are already throwing often. They would be well served to start throwing early.