Because energy does not disappear into thin air? If you put energy into a shield, it has to translate into work of some kind and/or waste heat (inefficiencies, etc.) This is actually one of the biggest arguments for shields 'outputs' not correlating to their defensive properties. There are very few ways to justify enormous quantities of energy being dumped into shields.Luke Skywalker wrote:Upon further thought, there is clearly a difference between the energy capacity of a shield and its "output". Of course, why this output is measured in joules, I have no clue.
And even when you can justify huge expenditures of energy into defenses, that doesn't mean it will neccesarily be a constant drain (again if the shield draws huge amounts of power, it will only draw as much as the work it must do requires. In that sense dumping massive amounts of power into your defenses at a steady state is both stupid and wasteful: instead you would have a battery or capacitor of 'shield energy', which the shields would draw on ot do whatever work they need to do and which can be replenished by the ship's power core as needed. And if you're talking in terms of storage, treating your shield 'output' as energy rather than power can make sense.
While ST tech cna have individual differences, much of their technologies are broadly similar, and if they can identify the kind of shield used and figure out its output, they should be able to figure out its defensive properties. After all I'm pretty sure they were able to divine their offensive capabilities as well and be able to deem they were no threat.This is false. Data quantifies the output of the shields, and Picard uses that information to draw the conclusion that a single photon torpedo should be enough to penetrate it. Surely, "output" does not connote, for example waste heat, because then a low output could simply mean that the shield is highly energy efficient.
So either way, there has to be a correlation between the "output" of a shield and its strength. But I will admit that I have no idea what the ratio is.