Disclaimer: I was torn whether to write this post or not as I admired the author's effort in tackling this subject but there are mistakes and fit issues that were not addressed, or address incorrectly, which will be explained with reasons. However, I hate to see an incorrect article posted on the AAAC article site so please pass this post to the author for further revision.
Warning: wall of text coming..
Some apparent mistakes:
1. In the measuring pictures of regular vs. short, the vertical measurements show the correct way to measure: 38R => 30 inch; 38S => 28.5 inch with 1.5 inch difference in length. However, in the horizontal measurement, the 38R is measured as 31 inch. That picture of 38R on horizontal view is incorrect.
2. As
@ItalianStyle said, the paragraph "However, the jacket on the left.." should be written as "However, the 38S jacket would be the better...". That is clear and concise, and no confusion about top/down or left/right pictures.
3. In the article the author implies that the 38S jacket is a better fit because:
"From the front, the jacket cuts him, visually, in half, and elongates his shorter frame."
In fact, if you look at the frontal pictures, one can argue that the 38R jacket has the hem *closer* to the mid point to cut the body (excluding head) in half. The 38S jacket is just too short and not reaching to the mid point.
Just to clarify about this so-called "cut-in-half" rule: when discussing about jacket length, one way that tailors determine the length is to let the subject worn shoes and stand naturally. Then measure from nape (back of neck with a bump) to floor distance. Then cut that distance in half to determine the jacket length.
That is the proper way to determine where the jacket hem should cut in half.
IMO, both jackets (38R/S on this subject) are too shorts and not fitted. If you break out a ruler to measure the distance on the picture, even the 38R jacket is too short for this subject. It seems that vertical distance of jacket just barely reach the top of the shoe, not even to the floor (ignoring picture distortion). That just proves that this 38R jacket is too short for this subject.
Furthermore, if you observe the button stance on the 38R (no need to talk about the 38S as it is too high), it is higher than the ideal location, the narrowest part of the torso. It should be lower by 1 to 1.5 inches. If the jacket is longer, which will lower the button stance and pocket placement, it will sit at a better location for this subject, and that leads me to discuss about the *pooling around the waist of the 38R jacket*.
The pooling around the waist is caused by the narrowest part of the jacket sits at a wider part of the body, not by extra fabric around the seat. From the side view, it seems that this subject has a little bit of upper abdominal fat that sticks out around the waist. The reason that the 38S jacket does not have this pooling is because it buttoned higher than this gut, so the narrowest part of the jacket did not sit around this gut, and therefore no pooling. On the 38R jacket, since the narrowest part of the jacket clinched to the gut and pulls the back to the front, you see the wrinkles on the lower back of the jacket. The author mis-explained this problem with extra fabric around the seat. That is incorrect.
4. The *jacket hem sits with respected to finger joints* rule has been proven unreliable as different people have different arm lengths. However, one can use the simple two rules to determine the proper length:
a. divide the body from nape to floor in half
b. cover his seat to his liking (ideally fully but exception can happen, explained later)
Once this length is determined, than he can observe where the jacket hem sits with respected to *his fingers* at rest, whether it is a thumb's tip, fingers cupping, first joint, or even at wrist (extra long arm). Then this point of reference will work *ONLY FOR HIM*, not for anyone except they have the same proportions of body height and arm length.
That is the proper way to determine the reference point for one's body, not the other way around. Just because the hem sits at the thumb's tip work for you does not mean it is generally true for everyone. One still needs to follow those two rules to determine the proper jacket length.
What if there is a conflict between rule a (cut-in-half) and rule b (cover one's seat)?
IMO, rule a is more important than rule b especially with exceptional body proportion. One can have a tall lean body (think Conan O'Brien) with short torso and long legs. he needs longer jacket to cut his body in half, and that will result in the hem sit way below his seat, which is fine for this body type. furthermore, if he chooses to wear a shorter jacket that just covers his seat, he will show those exceptional long legs all the time, and that creates an illusion of short jacket on him. On the other hand, for a short statue with long torso (short legs), rule a still works because the jacket hem could sit not fully cover his seat, but with a properly fitted trousers with full enough thigh spaces, there is less broken visual transition from jacket to trousers. If he insists on getting the hem to cover his seat in this situation, it will result in too long the jacket and also illustrate his shorter legs, which is no good for his appearance.
In short: check rule A first and see if rule B can be met. Rule A should determine the *longest* jacket length that you can wear. If you are gifted with longer legs, play around with a shorter distance until you reach the place for rule B. For example, if one wears a jacket with BOC (bottom of collar with T seam) length of 31" and the hem meets this ideal point of rule A, this is the maximum length he can wear. However, if he has longer legs, a jacket with 30" from BOC just barely covers his seat, but show more of his legs, this length can be his ideal minimum length. Therefore, any jackets with length in between 30" and 31" will work for him, no matter which chest size. This can range from 38R to 42R depends on cuts or trend/fashion and his built. As long as the chest/shoulder and BOC length fit, the rest will sit closer to the ideal locations.
So, for a quick summary of determine one's ideal jacket length:
1. know your chest size and get a jacket that fits your shoulder (no shoulder divots and lapel bowing). Don't worry about the sleeve length as that can be easily shorten (except for functional button holes one).
2. use rule a and b as your guide line to determine your ideal jacket length
3. measure the jacket length from BOC to hem to determine this ideal jacket length *for you only*
4. observe where this jacket hem sits w.r.t. your hand and use that as a quick guide for you only.
Once you established your own set of guidelines, when putting on a new jacket, you can immediately tell whether that jacket has the right length *for you*. Is it too short, too long, or acceptable. How much shorter/longer is acceptable? That is entirely up to you. Maybe the jacket is too short, but you can now articulate how short to ideal and why you choose to wear it.
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Now, speaking of fit, I am questioning whether the size 38 fit this subject or not. Looking at the pictures, one can observe many traits of mis-fits: shoulder divots, tight chest (bowing lapels), high button stances, short jackets, wrinkles around the back and what not. It seems that this subject needs a size 40 jacket, and probably a 40R jacket with longer length. With his sway-back posture, narrower shoulder and a bit barrel torso, a fuller cut 38 or a 40R with wider armhole should fit him better.
Furthermore, his shoulder slope seems steeper as one can observe a somewhat concave curve on that 38S jacket. That suggests that he may not need too much shoulder padding on the jacket. An un-padded or lightly padded jacket should fit him better.
I should stop here now.