Grading from body measurements pt. 3

This is part three of an ongoing discussion about N. A. Schofield's article Pattern Grading found in the Sizing in Clothing book. Part one is here, part two here. I recommend reading the previous parts of this series before reading this one.

So what were the results of Schofield's experiment? I can't reproduce the actual results here, but it was something like this.

Imagine the square is a bodice pattern piece in one size. The star is supposed to be the same pattern piece but graded to the next size. Clearly, the two shapes have no proportional relationship to each other. The problem is further compounded by a different grade for corresponding pieces.

Imagine these are front and back bodice pattern pieces. Each corresponding pattern piece was graded separately based on the measurement data for that body location. Now imagine trying to sew the front and back together. It can't be done. Schofield freely admits the difficulty in the results. Though she also believes we need to learn how to deal with new shapes in pattern pieces in order to achieve superior fit.

Schofield's experiment left me with a lot of questions. I did not understand completely why she rejected the ASTM measurement data, nor why she went back to essentially raw data. Her grading methodology left me a bit confused. The results were clearly not suitable for industry application. Superior fit is the holy grail of fashion, but I'm not convinced that grading is the entire source of the problem. Superior fit, for each individual might only be achieved on an individual basis. In this case, 3D body scanning and customized clothing is the answer, but is it practical?

I would like to see this experiment repeated. The factors that will impact additional experiments are the measurement data and grading methodology. Why not use ASTM measurement data? Why not use traditional grading methods? I always support those who are willing to test ideas and theories. This was a worthy attempt by Schofield to ask important why and how questions.

Grading from body measurements pt. 2

This is part two of an ongoing discussion about N. A. Schofield's article Pattern Grading found in the Sizing in Clothing book. Part one is here.

My initial reaction to the idea of grading from body measurements was, "Well, of course we should." And in fact, we do for children's clothing. It seemed rather obvious to me to look at children's clothing as a model. Children's sizing is based on the idea of growth, meaning that the measurement intervals between sizes are not always consistent.

Let's look at an example for a 4-6x size range.*

For sizes  4, 5, 6, 6x
Chest: 23, 24, 25, 25.5
Waist: 21.5, 22, 22.5, 23
Hip: 23.5, 24.5, 25.5, 26.5

The grade works out to be, choosing size 5 as the base size:
Chest: 1, 0, 1, 1.5
Waist: 0.5, 0, 0.5, 0.5
Hip: 1, 0, 1, 1

In this example, we have a 1" chest grade, except for size 6x which is 1.5". The waist is a 0.5" inch grade and the hip returns to a 1" grade for all sizes. Each body measurement area has it's own grade.

In women's clothing a 2" grade means that the interval change between the sizes will be 2" for chest, waist, and hips. Though even this isn't true across all brands, and you will find variations. (IMO, this is a good thing)

I don't know the history of women's sizing well enough to explain how this mode of practice came to be nor exactly why. It is clear that it does make grading, especially hand grading, much easier in practice. It is also unclear to me that grading is the source of our fitting woes. Nevertheless, it does make sense to me to go back and look at body measurements and devise a more precise grade rule.

The question then becomes, which body measurements do we use? In my children's example above, the numbers are still nice and easy to work with. The body measurements have been intentionally manipulated to be easy to work with. Raw measurement data was averaged, sorted, and studied to arrive at some numbers. Those numbers were not easy to work with, so a group of industry professionals sat down and made them that way. They modified certain measurements by about 1/8" to achieve consistency. Their modifications were rather minor and easily fall within a statistical margin of error. If you read their reasoning, it makes sense. This manipulation of measurement data for ease of use continues today in more modern measurement studies. It seems deceitful, but at the end of the day is infinitely practical. ASTM D4910 inherits this method of data handling from the measurement studies done in the 1940s, but does provide some updated measurements.

Looking at the Misses body measurement chart, ASTM D5585, it seems to be arranged and handled in the same way as the children's body measurement chart. IOW, the chart does not show a 1, 1.5, or 2 inch grade in the body measurements. It is a lot like the children's example above. There does seem to be a disconnect between measurement data and grading, at least on the surface. Individual companies will decide how to interpret and implement measurement data, and therefore their grade rules. (IMO, I think this is a good thing). And some will use a 2 inch grade, and some will not.

So what measurement data did Schofield use? She rejected the ASTM charts and created her own version of measurements derived from body measurement studies. This presented a problem because measurement studies do not always include the measurements needed for pattern making and grading. Schofield did not normalize the data, in other words make it easy to work with. Also she had to figure out how to deal with missing measurement data. I no longer have a copy of the article and can't look back, but Schofield selected certain measurements over others. How and why she handled those measurements puzzled me.

I believe Schofield's goal was to remove the idea of maintaining an ideal proportion or predictable pattern shape. She wanted to see what the body measurements really did between sizes.

Her results were almost predictable. More on that later.

*These measurements come from the withdrawn child measurement standard CS151-50. Measurements are in inches.

Size standardization for clothing

In academic circles there is the idea that we need one measurement and sizing standard to solve all our fitting problems. A top down approach with no allowance for variation. Customers often complain that manufacturers have no idea what they are doing because nothing ever fits. Manufacturers face an enormous challenge in trying to interpret size specifications while at the same time meeting the needs of their customers. The more I read about sizing the more chaotic it seems. At the end of the day there is more than one way to look at size standardization, and I think only one battle to fight.

One standard to rule them all

Yes, the idea that one standard can be established for everyone. By forcing compliance we will have peace on earth, and yes, our clothes will fit! Considering the variety of shapes and sizes in the United States alone, the idea is really a fantasy.

• One standard guarantees that some of the population will not have any clothes that fit. One could argue this situation exists today, so why not try one standard. With no allowance to adapt to fit the wide range of shapes and sizes, then outliers will never have clothes that fit.
• Our population is constantly changing. The most recent sizing study revealed that we are taller and weigh more than we did in the past. One standard would quickly become outdated.
• Sizing studies are very expensive and labor intensive. Studies are not done frequently, so manufacturers will always be behind what is happening in the real world.

Loosely conforming to a standard while yet adapting to meet a customer's need.

Even if one standard to rule them all is unrealistic, we still need a standard. ASTM and the latest Sizing USA study have provided us with a standard that any manufacturer can use (for a price, of course). These measurement and sizing specs can act as a guide, a place to start. As a manufacturer develops their customer profile, they can adapt these standards to meet the needs of their customer.

Over the years, it's important to compare your product against these standards. I've seen patterns and sizing drift from these standards naturally through errors. These errors are not intentional, they just happen and can easily pass from one style to the next. So a careful study and comparison can bring things back. This includes measuring fit models and comparing them against the standard and analyzing customer returns due to fit issues. 

In-house size standardization

Once a sizing standard is established for a brand, it is important to adhere to that standard during product development. As an example, all new pants styles have the same finished length and waist sizes as specified. Variations in fit can come from multiple sources due to fabric variations (or problems), construction issues (taking too big/small a seam allowance, cutting errors), or variations in a pattern. You have to be careful not to draft a pattern from scratch every time. Pattern makers in the industry will use the patterns from an already proven style to develop the new style. This practice ensures consistent fit across styles. A quality control process through each step of development and production is necessary to find problems before they become big ones.

A few words on vanity sizing

Vanity sizing implies that a manufacturer wilfully chooses to ignore a size standard and relabel a size smaller than it actually is. I do not believe there is a vast conspiracy to do this intentionally. Instead I think manufacturers are trying to meet the needs of their customers while trying to conform to a standard.

*This blog entry was inspired from my reading in the book Sizing in Clothing and more specifically the article Sizing Standardization by K. L. LaBat. I made very few notes on this article and don't remember much of what I read. I did make a note that LaBat tried to prove the existence of vanity sizing by studying children's age-based sizing. I thought the argument was rather weak.

Who creates grade rules?

Some one asked me a grading question the other day. She wanted to know who creates grade rules?

A pattern maker, grader, or you could make the grade rules. If you choose to make the grade rules yourself, I have some guides available in The Organized Fashion Designer and The Simple Tech Pack. It's harder with children's clothing because there isn't as much standardization. An experienced grader should have some standard charts or be able to develop rules off of your measurement charts. I would personally start developing grade rules by referencing the Jack Handford book and make modifications as needed. I would only let a pattern maker or grader do it who has experience with it.

You can buy measurement charts from ASTM as a place to start. The ASTM measurement charts for children are probably the best resource for children's body measurements. Be cautious of using free charts found on the Internet. I have seen free measurement charts on the Internet riddled with inconsistencies that could lead to serious errors.

If you have time, you may want to sew up the smallest and largest sizes just to double check the grade and sizing. It doesn't have to be in your production fabric or anything. A fitting is the only way to know if your grade is correct. You won't need to do this on every style or very often. Kind of important when starting out though.

Neck Opening Circumference

Please note: Body measurement charts for infants which include the neck circumference measurement are now available in my book The Essential Guide to Children's Clothing Sizes, available on Amazon.

Libetty left a comment on a recent blog entry and I think the answer deserves its own blog.

So I have a sizing question that you may be able to answer... What is the minimum neck opening circumference that a child needs to get a garment on over their head? I've always thought that it was 18". Is this correct???

Babies are very interesting. Most babies have the head circumference that they will have as adults. There is some growth that occurs between newborns and older babies as the bones in the skull begin to fuse and the head takes shape. Other factors that contribute to head size are genetics and weight. A newborn baby's head circumference may start as small as 14 inches but grow to about 20 inches by age 2. Proportionally, babies appear top heavy because the head looks too big in comparison to the rest of the body.

When designing clothing and patterns for babies, there are some other considerations. Babies do not dress themselves. This means someone else must be able to reach into a shirt, for example, and comfortably pull it over the head. With a dress, you have to reach down through the neck and pull a dress over the hips and ultimately over the shoulders. Some degree of space must be included to allow for ease in dressing (as quickly as possibly too!).

The recommended head opening for children's clothes is 20 inches for all infants and 21-22 inches for toddlers and up. This is a minimum measurement. Additional ease may be required depending on the fabric and/or style. This recommendation comes from my experience working with big box retailers - and they all seem to agree on this point. Over the years, I have seen that this is the measurement that is actually needed. BTW, this measurement refers to the extended neck measurement (see pictures below). There is no US government regulation that I know of - this is an industry standard. You can measure lots of product yourself to see most things follow this guideline.

Incorporating 20 inches into a neck circumference can be very difficult. The assumption is made that the neck circumference of the pattern must meet 20 inches. A neck circumference on a baby is 12-14 inches (measurement taken at the base of the neck). If your pattern has a neck circumference of 20", then your garment will probably fall off. The extra girth needed to meet the extended neck circumference can be added by the addition of a front or back placket, zipper, button placket, lapped shoulders, elastic, or stretchy neck ribbing. In other words, make the neck of the pattern where it should be and add extra length/girth somewhere else.

Here are few pictures of me measuring the extended neck circumference of a few different styles. Please note, I used a tape measure because it shows up better in the pictures. You should probably use a flat ruler instead. Plus, DH was taking the pictures off to the side, so it appears that I am not lining things up right, but I am. To measure the extended neck circumference, place one finger in the center front neck and another in the center back and stretch. Double the measurment from the ruler and you will have the extended neck circumference. If drafting a pattern, you can measure the pattern neck circumference plus any additional opening. It is best to double check a measurement after a garment is sewn up because things change.

This shirt has an elastic neck. Stretch the elastic as far as it will go without damaging it. You can see this neck measures about 22" extended.









This infant polo shirt has a front button placket. You can see this shirt stretches to 20".










This infant t-shirt only stretches to about 18". It is a bit tight IMO. Part of the problem is the stretch of the ribbing and also how it is stitched to the neckline. The topstitching prevents stretching beyond this point and could actually break if I take it any further.






To measure the neck opening of a dress, measure from the center front neck to the bottom of the skirt placket opening. The extended neck measurement needs to be larger because the waistline needs to either slip over the head or the hips easily. This measures about 26 inches.

Creating a grading standard pt. 3

2019 notes - The original images for this blog entry have disappeared and I haven't had time to recreate them. I do have more complete examples in my ebook, The Organized Fashion Designer.  
 
I finally made my example measurement/grading charts. It took a little dancing as I had to create them in a spreadsheet, export them as a PDF and then convert them over to a jpg. Before I get too far, it may be helpful to review my previous blogs on grading: Creating a grading standard and Creating a grading standard part 2. You should have your own measurement charts handy. BTW, the measurements in my charts are real. I found them from the Sears website. I do not necessarily endorse Sears measurements as the industry standard - they were just handy (To be fair, their measurements are pretty good). Your own measurement charts should be far more complete and detailed than these for pattern development and actual grading anyway. This is the first step I take in developing actual grade rules.

Right off, I hope you notice a few important things. First, I have clearly marked my sample sizes. In this example they are sizes 10 and 10+. Each chart is labeled clearly. You would think these things should be obvious, but you would be surprised at what I have seen. Hanging off of the left side are numbers. These numbers are points of measure and should correspond to a How to Measure diagram (a future blog) and are not relevant for the immediate discussion. Also notice that my size ranges differ. The regular sizes run 7-16 and the plus sizes run 8+ to 18+. This is a fairly typical difference between the two groups. Also notice the difference in the measurements. There should be some obvious differences between a Misses and a Plus sizes chart too.

Usually, I have my grading chart separate from my measurement chart. I combined them here so you could more easily see how I am developing my grading rules. In the column for my sample sizes, I have placed a zero. A sample size is also called a base size in grading. It is your starting point and each subsequent size will grow or shrink proportionally off your base size. Next I subtract the difference between the base size and the next largest size. In the regular size chart, you will notice there is a 1.5" difference in the chest measurement from a size 10 to a size 12. This difference is called a grade step. Next I subtract the difference between a size 14 and a size 12. I don't subtract Size 14 from a size 10 because that is not the next grade step. Continue to subtract the next larger size with the previous size.

To calculate the grade for your smaller sizes, subtract your sample size from the next smaller size. Be sure to add the negative sign, which indicates the grade is getting smaller. Repeat by subtracting each size with the next smaller size. Create a grade for each measurement on your chart.

You will notice that the measurements and grades all have beautiful numbers. The measurements increase or decrease proportionally causing the grades between sizes to be relatively the same. This is where the art of grading and measurements come into play. I can guarantee that actual body measurements are not this pretty or consistent. These numbers have been averaged and rounded and are based on a large body measurement sampling. The numbers have been intentionally made easy to work with. Your measurements should be easy to work with too and you can adjust them as necessary.

What about accuracy? Rounding does introduce inaccuracies in your measurement charts, but only a little. If you look at growth charts, you will find that certain measurements will fit 50%, 80%, 95% or 97% of girls. If you adjust your numbers up or down, you will want to make sure those numbers fall into the 95% percentile. Adult measurements and sizing are similarly developed. Because these measurements are based off of measurement studies, it means a real girl will pick the size that most closely matches her measurements. Your measurement numbers just need to fall within the highest percentage category. You can round to the nearest 0.5" or 0.125", or whatever. Adjust your measurements so that you get a relatively consistent and even grade across the sizes. In my regular sizes I have a consistent 1.5" chest grade and a 2" grade for my plus sizes. Sure, you could throw in what ever grade steps you choose as long as you have justification for it.

Finally, I hope you can see the difference between the regular and plus sizes. Not only are plus size measurements larger, they are proportionally larger (the grade step is larger). This is why you absolutely cannot grade a plus size pattern from a regular sized pattern piece. Keep both categories, pattern pieces, measurements and grades separate from each other. I promise it will save your sanity.

I know this is a lot of explanation for this first step. If anyone has a question about this, just leave them in comments and I will try to answer them. In my next article in this series, I will explain how to create grade rules based off your first grading chart.

Creating a grading standard pt. 2

In a previous blog, I wrote about the first steps in creating a grading standard, but failed to discuss the details. It would be helpful to also review my blog entry titled Too Many Sizes! In this blog, I will try to explain grading terms and the rules by which grading can occur. In the future, I will show how to develop your actual grade rules and how I grade a pattern (which is different from any other method I have seen).

There seems to be a lot of confusion about grading. Some people view grading as a magical process that can turn your beautiful pattern in one size into any other size you desire. Before anyone can grade your pattern, you should have already done some homework. You should have chosen a category, size range, and measurement chart. Your category and size standard should be fairly simple. You should only be working in one category and your size range should not have more than 6 sizes. You may want to work in men and womens plus and regular sizes all at once, but it is just not possible.

Now, I have to stop here for a moment and explain the concept of categories. I don't know if this is the appropriate term or not. I work in a children's category, but you may work in Misses, Juniors, Mens, or whatever. Within those broad categories, there are sub-categories or classifications based on your sizing system. A classification is based on a specific figure type such as Misses, Petites, Plus, or Talls. Each of these designations have a separate and distinct sizing system. You can't magically start with a Misses size and turn it into a Plus size by grading it. That is not how grading works, so don't even attempt it. There is no magic formula.

Grading is a simple, yet difficult concept for people to grasp. Grading is a process by which a base pattern is proportionally changed to create smaller or larger sizes. Grading is always based on a set of measurements specific to a size range and classification. Successful grading does not change the overall proportions of the intended design as the size changes. This is why a size range should be limited to about 6 sizes. Any more than that and the largest or smallest size will be proportionally wrong.

Successful grading is all about having a good starting point. A base pattern is a pattern created and perfected to fit a sample size. From that base pattern, you will create the other sizes in your size range. Now some of you want to offer Plus sizes in addition to your Misses Sizes. It should be as simple as grading your base Misses patterns up to the appropriate plus size, right? After all, it would save a great deal of work. You already have a perfect pattern and why would you want to go to the work of creating a whole new set of patterns.

The reality is, you will have to create a whole new set of patterns in a new base size contained in a new size range and classification. I know this sounds like a lot of work. The truth is that it is, at least initially. You will have to develop a set of base patterns for your Misses sizes and a separate set for your Plus sizes. You may sample a new style in a Misses size initially. Once a style is approved, your patternmaker will then create patterns in any other size ranges you want to offer. The process required to create the plus size patterns will be very similar, if not identical, to the process required to draft the Misses size patterns. There may be a little tweaking for fit during sampling, but the process will be faster than the original style development. Your patternmaker will already know what should be done.

For example, one company I work for will create a new style in a size 5 (in a children's size range of 4-6x). They then decide they want to offer that style in the entire range 2T-16 and plus sizes. I have already broken up the sizes into ranges of 2T-4T, 4-6x, 7-16, and 8+ to 20+. I then make patterns in the sample sizes of 3T, 5 (which is already done), 10, and 10+. The patterns for each sample size are then graded within their range. It may sound like a lot of work, especially if done entirely by hand. Since I work in a CAD environment, I can accomplish this task in less than a day. By hand, it may take 2-3 days.

Going back to our previous example......Once your set of Misses patterns and Plus size patterns are finished, you will then send those off to be graded. And this is where you have to create your grade rules. To create grade rules, you will need your measurement charts. So here is your homework assignment. Read your measurement chart. If you are offering more than one classification, compare the two. How does a Plus size differ from a Misses? Do your measurements make sense? Do the measurements decrease for the smaller sizes and increase for the bigger? In the next blog, I will show how to create your grade rules from your measurement charts. Once you see the grade rules, you will then understand why you can't grade a Misses size into a Plus size.

Sizing Up Children pt. 2 : How to find size charts for children

"The problem is children’s clothing manufacturers cling to their 30+ year old size charts. They protect their sizing information like a trade secret (not uncommon in every segment of the fashion biz). And while major studies are being done on men and women, they are not being done on children. (If I am wrong, please let me know)."

After doing some more reading at fashion-incubator, I discovered I am only half right. The 30 year old study on children's measurements done in 1975/1977 is publically available here: Anthropometric Data of Children. This is the data that most manufacturers continue to use. Since it is freely available, there is not much incentive to change. I have been using size chart information based on this data for at least 10 years because this is what the companies I worked for used. To be fair, it is still fairly good information.

Another source for sizing information is available from ASTM International. Kathleen Fasanella at fashion-incubator.com lists the documents to search for at her blog: How to obtain sizing and grading info. This data set is updated about every five years or so. Even though the data information is priced fairly, you still need to buy 3 charts to cover all children infant through teenagers, a price of about $90. The other thing to consider when purchasing from ASTM is that you only license the information. Be sure to read the license agreement! You are given permission to download on one computer and print out only ONE copy of the charts. You also give permission to ASTM to come and inspect your company computer and materials at any reasonable time to ensure you are complying.

As a small company, I do not like this license agreement. What if I have two or three technical designers who need access to this chart? My costs for this information multiplies! Plus, who wants to allow some other company/organization to come in and inspect your premises at will?! I wonder if ASTM has ever tried to enforce their license?

I also don't like the propriatary nature of the data. The only way to get cooperation from businesses to standardize is to make the information available for free. I realize as an organization they need to make money to support a needed role. But they could take a hint from other opensource projects and raise money by donation or some other model.

Because of the difficulty with ASTM, I now understand why companies continue to use 30 year old data.