Slopers

I've been meaning to write this post for ages, but never did until I got Stasia's most recent newsletter about her jeans-buying adventure, and thought I really should get to it.  I think a lot of people don't understand why sizing varies so much across and within brands, and get frustrated when a size doesn't fit the way they expect.  I didn't understand until I started sewing for myself and reading about the fashion industry, and I found the knowledge so helpful and empowering!  Hopefully this will be helpful for someone out there.

The short answer is that when you make a garment and size it up or down, you use what is called a sloper.  The sloper is the base pattern that is used to make all the other sizes from, and where brands slope from and who they slope for, determines a lot of how garments fit proportionally.  (I have a larger-than-industry-standard waist-to-hip ratio and a 14" rise, so I've never been able to find RTW pants that fit me, and modern skirts are usually a challenge). 

The first thing is that some brands slope from the middle of their size range, and some slope from the bottom.  Sloping from the middle means that whatever the "medium" or middle size number is (often an 8, but sometimes a 10), is the base sloper.  The smaller and larger sizes are then graded from there, which means that the pattern is either made larger or smaller along the seam lines in even increments.  Some brands slope widely between sizes, and some slope smaller.  What that means is that in some brands, the difference between and 8 and a 10 might be an inch or more, and in some brands, it might less than an inch.  A common grade is 1/2" between sizes.  The size differences are more pronounced the fewer sizes there are overall, so things that are simply labeled: small, medium, large, etc. can vary quite a bit.

For brands that slope from the bottom of their size range (say a 0 or a 2), their upper size range is going to come out much smaller than a brand that slopes from the middle (this has to do with how grading is done, and how much grading you can do to a pattern before it starts to have distortions.  It is also why so-called "plus-size" clothing tends to start at a size 12 or 14, because it is difficult to slope from size 0-30 without having at least three base slopers made, which is expensive). 

There is also the target audience of a brand, which is useful to know not because of style-sense, but because it informs the slopers.  Brands that market to a younger audience are likely to slope from the bottom of their size range.  Why?  Because their target audience is a teenager with a still-maturing pelvic cradle.  So these brands' slopers are smaller, the size range smaller, and the amount of curve smaller.

JCrew slopes for a taller-than-average, straight-up-and-down figure, and appears to slope from a size 4 or 6, and their clothing reflects all that.  Land's End and LLBean target a different audience, and appear to slope from the middle of their size range, but the middle of their size range is also based on a curvier figure. 

Slopers also change over time, which is why a vintage 14 is considerably smaller than a modern 14 in almost any brand.  Legacy brands like Pendleton or Eddie Bauer have vastly different garment measurements over time.  I thrift wool skirts online, and never purchase anything from a legacy brand that doesn't have the measurements listed because you can't go by size.  A vintage 14 Pendleton skirt (from 1990s or earlier) is going to have somewhere between a 26-28" waist and 36-38" hips.  A recently-made Pendleton skirt in the exact same style, in the same size, is going to be more like 30-31" waist and 41-42" hips.  I recently discovered that Sag Harbor made a wool skirt sometime in the 1980s or early1990s that fits me great in a size 14, but not all my 14s are the same.  Some of my skirts have a 32" waist, and some are more like 31" (these skirts have a bit of elastic in the back, so some of the range might be due to how much the elastic has been stretched out, but it is hard to tell).  This is for the same skirt, in the same woven, non-stretch fabric/lining, made around the same time. 

The other issue is that there isn't a standard sloper for any garment across the fashion industry, but in jeans, particularly high-end jeans, companies often do not check their slopers carefully against actual women's bodies for good fit across all sizes.  What happens is if there is a basic fit issue on the sloper of a high-end jean, it gets replicated across all the jeans in that range and brand, and in all lower-cost brands that copy their sloper.  Sometimes you also get slopers that grade well up or down one size to either side, but distort big-time when you get more than a couple of sizes up or down.  Since the fashion industry moves fast these days, there isn't enough time to check all these things because time is money and clothing has become more or less disposable.

I think one of the reasons why so many "pear-shaped" (or triangle-shaped) women have trouble finding pants (*raises hand*) is that no one has bothered to check slopers for full seat adjustments, because as your waist-to-hip ratio increases, the likelihood of a fuller seat increases.  (So does the need for a full tummy adjustment).  Since many brands are sloping for a 6-8" waist-to-hip ratio (meaning that the waist is 6-8" smaller than the full hip measurement) and a flat bottom and tummy, anyone with a differently-shaped body is going to have major fit issues at any size.  Stretch fabrics can only mediate fit issues so much.

I personally find garment measurements to be the best predictor of fit (know thy measurements and thy desired ease of wearing!), and since I thrift most of my clothes online, I try not to buy unless I'm pretty confident about the measurements or I've had a lot of experience with the brand.  

If you've made it all the way to the end of this, pat yourself on the back!  I hope this proves helpful.  The main thing to remember is this: your body is not a problem (All Bodies are Good Bodies!), and size is just a number.