Hi Joblin. While not directly related to the P-38, the stuff below seems relevant, at least to me, when talking about losses and kill ratios.
You have to define your terms quite carefully.
By way of example, take the F6F Hellcat in WWII:
1) The US Navy suffered 270 F6F losses to enemy aircraft in combat. The F6F shot down 1,445 bombers and 3,718 fighters for a total of 5,163 victories. That's a kill ratio of 19.12 : 1, usually quoted as 19-to-1 in "air-to-air combat."
2) We also lost 553 F6Fs to enemy AAA, though these were action sorties by definition, they were not air-to-air combat losses. An AAA guns sit on the ground; they don't fly. Fighter pilots can't dodge AAA rounds because, a) they can't see them coming, and b) if they could, the rounds come much faster than enemy airplanes do. Notice we lost about twice as many to AAA as to enemy airplanes.
3) We also lost 340 F6Fs on Operational flights when we saw no enemy but we engaged in partol or general fleet defense routine flying. Again, not air-to-air combat losses, non-action sorties.
4) We also lost 885 F6Fs on other flights, such as repositioning, deployment, moving between bases, etc. Again, not air-to-air combat flights and no enemy was encountered ... non-action sorties.
5) We lost 413 F6Fs on ship or gound when not in operation. That is, the F6Fs were on a ship that sank or when the F6F got consumed by fire or explosions aboard ship that was attacked or suffered an accident or was destroyed sitting still on the ground by enemy aircraft or some other way. These are not sorties, action or otherwise. They are aircraft lost when not actually flying. How do we account for these losses?
6) The total of all losses above is 2,461 as opposed to 270 lost in air-to-air combat against enemy airplanes. 2,461 losses against 5,163 victories is a kill-to-loss ratio of 2.1 : 1.
You COULD break out losses that happen only while flying and you get a number between 2.1 :1 amd 19.1 : 1 but, if you do, then you are mixing losses on action sorties with losses on non-action sorties. Should it count against that airplane's reputation if the pilot was stupid enough to run out of fuel and ditch in the ocean? What about if he forgot to use carb heat and wound up ditching due to carb ice or propeller failure of some sort, or an engine that packed it in during a maintenance flight?
Most people look at WWII losses against enemy airplanes versus combat victories, so the F6F has a ratio of 19.1 : 1.
But, depending on how you lump losses together, it could be as bad as 2.1 : 1.
As they say, you can make statistics say almost anything you want if you lie creatively enough ... caveat emptor. You need to look very carefully at how things are calculated to be sure what the numbers you see in print actually mean.
If a pilot has 3 aerial victories but has destroyed 5 of his own aircraft due to accidents or running out of fuel, is he a combat asset, an enemy ace, or what?
Personally, I look at aerial victories against losses in air-to-air combat with enemy airplanes. Operational losse are more related to the quality of the planning, maintenance, and general operation of the airplane than its combat reputation. AAA losses are more severe than most people think they are. Overall, in the US Navy during WWII, we lost 907 airplane to enemy aircraft while we lost 1,982 to AAA. That's 2 : 1 for losses due to AAA over losses due to enemy aircraft. Basically, 1/3 of all our action sortie losses were due to enemy airplanes and the other 2/3 was to AAA. So, we'd have had 2/3 of our actual losses even if we didn't lose a single aircraft to enemy fighters / bombers.
It's worth thinking about in some detail.
The numbers above came from Table 1, Naval Avation Combat Statistics World War II, OPNAV-P-23B, dated 17 Jun 1946, available online as a pdf file.
The definition of a "loss" is also fraught with difficulty, and is worthy of a dedicated thread. Just to scratch the surface, if a plane gets damaged in combat and is later flying home to the carrier when the engine catches fire due to an oil leak, and the pilot bails out, should that be classified an oprrational loss or a combat loss? What about if the airplane is damaged in combat and flies home and lands without incident, but is then later scrapped because the damage was too severe to repair. Is that a combat loss? Or did we scrap it beause we didn't have time and manpoower to fix it so we just pushed it over the side of the ship?
Again, things can happen that make classifying the event a tough decision.
Cheers!