The actual scale is completely inconsistent.
imo, there's no real scale
These are really misleading statements. (Also, the OP asked about human figures, not Jabba, Vehicles, etc.)
Imperial Assault human-sized figures are 1/56 scale.
Granted, there is some variance, but Imperial Assault is much more consistent than other miniature systems.
Imperial Assault human figures match up with WOTC Star Wars Miniatures, Games Workshop, Privateer Press, Bolt Action, Infinity, etc. It's the same scale as popular game systems that call themselves "heroic 28mm scale." This generally means that a 6 foot tall person is about 32mm.
Imperial Assault is not the same scale as Star Wars: Legion.
Legion miniatures are 1/46 scale, which means the same figures are generally a full head taller than the same Imperial Assault figure. So a Legion Stormtrooper is 7-feet tall in Imperial Assault.