Just like adults, children come in all shapes and sizes. Lutterloh does have a size standard that they design for to help us judge what size we should be working from.
Unfortunately neither of the children I sew for fit this scale that Lutterloh uses. This doesn't stop me from using the Lutterloh patterns for children with great success though. For children Lutterloh wants us to use only the chest measurement. Even very thin and rather plump children still have little shape to their torsos so the chest is usually the largest measurement we need to fit. An exception to this rule would be for a very round child whose tummy extended past their chest measurement. In this case you may need to use the waist measurement to fit pants and skirts. The key is to make sure to choose patterns in the correct size range and make adjustments for length.
So how do I decide what the correct size range should be? Well it just so happens that both of the children I sew for are 5 years old. However, both of them are very small for their age. My friend's son I'll call "R" is just small all over and rather short legged. His chest measures 56cm. My niece "K" is very thin and only slightly shorter than her classmates. Her chest measurement is only 54cm. As you can see, compared to the chart neither of them come close to what Lutterloh thinks a 5 year old should measure. I typically choose Lutterloh patterns in the 2-6 year range for them. According to the chart K doesn't yet fit into the 2-6 range but I know she has a vastly different shape from a 1 year old baby. Choosing patterns for a baby for her would result in garments that were way too short all over. Babies tend to have shorter, plumper limbs than older toddlers so I at least need to stick with a toddler size range.
You'll see from the 1976 photo above that Lutterloh generally tends to categorize their patterns in ranges that cover about 4 years with some overlapping going on. If you had a rather "large for their age" 4 year old you might very well be able to use all the patterns on this one page. I have found that for K I can now use patterns in the 2-6 up to the 4-8 range. Because I use her chest measurement my patterns fit great in all the circumference areas but because this measurement is so small I then need to lengthen them all. The smaller range patterns I usually only need to lengthen a couple of inches but I recently drew out top and pants patterns in the 4-8 range that I needed to lengthen by more than 5 inches.
So, when deciding what size range to use for your child, you need to consider their stature as well as their measurements. Ask yourself is my child average sized compared to other children their age? For very petite children you may need to use a smaller size range than their age. For the bigger, fast growing children you may need to use patterns intended for slightly older children. Just remember to always at least paper fit your pattern before cutting out your fashion fabric. This should give you an idea if you need to make any length or ease adjustments before any fabric is wasted. If your child is far from average it might be a good idea to make a test garment in an inexpensive fabric first. This will help you determine the adjustments you need to make to all the child's patterns in this range. At least until they grow again. :)
for more info on the patterns Ann will be using for K's gift.