The most interesting observation I made was color. Everything worn was gray or darkest blue at the flashiest. I was surprised to see no analysis of color. It would be interesting to quantify if the author's "bottom half" was generally 5% darker than the author's "top half" or maybe the opposite or maybe it averages out exactly the same.
I live in a 4-season state and I would be pretty interested to see if I, or people in general in my area, vary their average clothing color by the season. I would theorize the people get tanned in the summer, intentionally or not, varying by race quite a bit of course, and that skin tone change would influence average clothing color selections. Another theory is I notice I wear slightly warmer-brighter clothes in the winter, in an opposition to winter's dreariness, I almost feel compelled to wear a bright Hawaiian shirt if its snowing. A third theory is people would wear lighter colors around the peak of summer to limit solar heating. A fourth theory I have is summer heat seems most comfy in clothing that's tighter or looser than average for cooling reasons and middle of the road size would the minimum of comfort in the heat, whereas in the winter middle of the road tightness would seem the best balance of warmth and comfort. These theories could all be wrong, or right, of course.
A completely different side issue is over the years I accumulate more self-created uniforms and I wonder if that would show up in the data. I have a uniform of grungy old clothes resembling the color of used motor oil for changing oil or similar greasy repair jobs. I have exactly one set of grungy clothes I wear when I paint that are all stained up so I don't care if I stain them worse. I have exactly one set of clothes for lawnmowing/yardwork, the specific type of synthetic seems to clean up well from tree sap and the shoes are a grass-stained lost cause. I have a set of clothes specifically for shoveling/snowblowing that "tech" stuff that dries quickly because sweating and cold equals hypothermia, or at least extreme discomfort. Most people already have that set of clothes they wear to the gym or other exercise, of course.