Power to mass ratio

Ok this one is confusing me a bit as the numbers don’t seem to give what we generally understand to be the definition. i.e. Power / mass = the ratio. I was looking at some You Tube game play videos and working through what was going on it seemed to indicate that the best ratio was 1/1 in terms of numbers. But after playing round in the game with various bits of kit of various weights(mass) then this doesn’t seem to be the case either.
The power/mass number seems to be a subtraction of power from mass or in some of the videos mass from power. if it was fixed i.e. always subtracting power from mass then in cases where the power was higher it should give a negative value. Whereas in the few cases I have seen the lower of the two always seems to be deducted from the higher.
Don’t need the full math behind what is going on, but any guide as to what we should be looking for to get the best balance here.

I’m 99% certain it’s just abs(Power-Mass). Your speed appears to be determined by how much power exceeds mass, which means a large number is good, except because of the absolute value a large number could also be bad. In short I would just ignore it lol, increasing power or decreasing mass both increase speed and that’s it.

Actually it’s not just the PMR, the game seems incapable of displaying negative numbers entirely - for example Hydraulic subsystems both decrease mass and heat dissipation but show positives, the Power stat on thrusters is actually a penalty, and “Plating - Empty” defensive subsystems say +x% to mass and integrity when in fact they do the opposite. It’s a significant problem in figuring out what anything does

Thanks An. Guess it’s just going to be trial and error. Adding in the negative sign would make things a lot clearer and not calling it power to mass ratio might help as that just confuses it with the actual real world calculation.

EDIT I’ve been playing around with this a bit more and sometimes it makes no sense how the speed value is increasing when changing parts. Changing a medium part for a heavy part gave a speed increase and that was with all the same subsystem, same level and same rarity. The three things I would guess have an impact besides mass. Definately trial and error.