There are studies and simulations out there that show that the traditional method by which we usually board a plane, back to front, is not the fastest way. A while ago Mythbusters saw that back-to-front board was even slower than purely random boarding. In their experiment outside-in boarding was even faster, and unassigned seating was the fastest. Of course Mythbusters doesn’t operate under any standards of statistical analysis or verification of results, but intuitively these results make sense. The faster methods allow for parallel boarding; multiple people can be stowing their bags and getting settled simultaneously, whereas back-to-front causes a build up of people waiting for their turn to have access to the overhead bins.
Another more recent study (Popular Mechanics article on the paper) used 4D models and simulations to study other factors involved in plane boarding. Here they found that having “slow-boarders” go first is overall faster than allowing the “fast-boarders” to go first.
All these faster methods seem pretty straightforward and could be easily implemented in an ideal world. What they don’t take into account are individuals’ realities. If you have families travelling together, separating the children from the parents for the sake of a few minutes quicker board time doesn’t make all that much sense. Classifying passengers as slow and fast also seems like it can be potentially insensitive or just come with its own social issues. AND all of this assumes that airlines want more efficient boarding in the first place. Sure they may have costs associated with flight delays and such, but they also sell priority boarding at a premium.
So were the outcomes of these studies every really going to change how airlines operate? Probably not. Does that mean those studies were useless? I don’t think so. But I do think it is good to recognize that just because something is ideal on paper doesn’t mean it could ever work in the real world, and the limiting factor will almost always be the human factor.