Partial Dreams Quilt Along: Week 3 Accuracy vs Precision in Quilting

Week 3 of our quilt along starts today! We’re going to be making 6 blocks today. If you haven’t signed up for the quilt along yet, you can do that HERE. I’d love to have you join us! Stragglers are always welcome in my events. So, you can still sign up as long as the quilt along’s still going. After you sign up, your welcome email will contain the pattern, schedule, and a run down of the extra fabrics options I added to make this quilt along more inclusive.

There isn’t anything new about these blocks compared to last time. So, for today I want to dig a little deeper into accuracy vs precision. We touched on this a little bit in the Week 1 and Week 2 posts when I talked about scant 1/4″ seams vs regular 1/4″ seams and where to start your 1/4″ seam when your precuts have pinked edges. But, a lot of people don’t realize that accuracy and precision are NOT the same thing. The “Accuracy vs Precision in Quilting” from the title is actually a little decieving because it applies in lots of situations, not just in quilting.

Before we go on with talking about how Accuracy and Precision are different, a little disclaimer. I’ll be talking about these two in relation to how they help you get your seams to match up. BUT, just know that is perfectly OK to not care about your seams matching up. Quilting is supposed to be fun. If fretting over the seams matching up stresses you out, then try to find a way to let that go and just enjoy sewing. If you aren’t enjoying it, why are you doing it anyway? There’s also nothing wrong with taking satisfaction in doing your best work. The person who doesn’t care about perfect seams and the person who unpicks stitches and redoes them until the seams are matching up aren’t hurting each other. We can all still be friends. There’s really no need for either side to put the other side down.

What is the difference between Accuracy and Precision?

Accuracy – how close something is to the true or accepted value
Precision – how close measurements of the same item are to each other

So, in other words. Accuracy describes being close to the “target”, and precision is about consistency. Accuracy and precision do not necessarily go hand in hand.

Most people use a target to illustrate accuracy vs precision because it’s an easy visual to understand. In the diagram below, I drew 4 targets, all with 8 red lines representing shots.

The top left picture in the diagram shows 8 shots that are all close to the center. They are accurate, but they are still pretty spread out, so they aren’t as precise.

The top right picture is pretty precise because all of the lines are clumped together. These shots were consistent, but not accurate because they weren’t close to the center.

The target on the bottom left shows that all the shots were clumped together in the center. This is accurate and precise. The poor archer in the bottom right corner didn’t get anywhere near the center and the shots were all over the place – not accurate and not precise.

Applying this to quilting

Let’s apply this to quilting. Instead of a bullseye, we’ll think of this in relation to that “perfect” 1/4″ seam. If you’re only a hair off of perfect, that’s more accurate than 2 hairs off of perfect. What if you’re never more than one hair off, but sometimes it’s a hair to the right and sometimes it’s a hair to the left? In that case, you would be less precise than the person who is always off by 2 hairs but keeps it on the same side everytime.

So, do we strive for accuracy or precision? In perfect practice, both accurate and precise is where we want to be if we care about getting seams to match up nicely. I’ll say this again for the people in the back: It’s perfectly fine to carry on quilting without stressing over seams matching up. Your quilt, your rules, you do you. Anyway, accurate and precise for perfect practice and all, but nobody is perfect all the time. Honestly, sometimes I feel like I just don’t want to have to care about both.

If you want your seams to match up (notice I said “IF”), there are some quilts where you can get away with consistency/precision only and some quilts where you have to have both. If your units all have the same number of seams, all going in the same directions, you can get away with just being consistent/precise. Be consistent and your block will turn out. Lets look at some examples.

In the picture above, you can see Checker Cakes #1 when she got to go to the Grand Canyon. I made that checker board quilt using all 9-patch blocks. Each block has the same number of seams, and they are all going in the same directions. So, I’ll be honest, I paid ZERO attention to getting a perfect “scant 1/4″ seam” when I was making those blocks. I just used my 1/4″ seam foot and kept the seam allowance consistent. I was able to get everything to match up nicely with no issues. The Partial Dreams pattern is the same in that all of the blocks are the same – same number of seams and all of the seams are going in the same directions.

Now we’ll look at Pinwheel Poppers. I wrote this pattern for Southern Charm Quilts’ Resource Library. You can get it FREE. This one is a fun pattern that I designed to be quick and easy. Some of the easiest pinwheels you could make. I can’t decide if these pinwheels or the pinwheels in Franken-Patches are easier. Anyway, as quick and easy as this one is, I still had to pay attention to both accuracy and precision to get the seams to match up.

All of the pinwheel blocks are made from 4 smaller units. These units have the same number of seams, but every other one has seams going in the opposite direction. Why does this matter? The units that have the vertical seams will be remain whatever length you cut the pieces to, but the width may not be the same if your 1/4″ seam is too big or too small. The units that have the horizontal seams will have the opposite affect. So, if you’re off by enough the 4 units in each block will be noticeably unmatched, and you’ll have to do a lot more fudging. If you have more complicated blocks with smaller pieces, this becomes more of a problem.

If that doesn’t make sense, you can try it out with your scraps. Cut 4 pieces that are 2.5″ x 4.5″. Sew 2 blocks using 2 of these pieces in each block. Sew the pieces together with a 3/8″ seam instead of a 1/4″ seam. Lay the 2 blocks side by side with the seams going in the same direction, and they should match up pretty well. Rotate one of them in the oppoiste direction, and you’ll see that the one with the seam going vertically looks a little longer.

So, if you can’t figure out why your pieces aren’t matching up despite accurate cuts and all of your seam allowances looking the same, this could be your answer. Accuracy and Precision/Consistency aren’t the same thing. You may just need a little practice with finding your 1/4″ seam. Use those 2.5″ x 4.5″ pieces mentioned in the example above. Sew 2 of them together with a 1/4″ seam. after you press this unit, measure it. Did you get a perfect 4.5″ square? If you didn’t, try again and adjust your seam allowance by a hair in whichever direction you need to go. Keep doing this: make the block, press the block and measure the block size until you find your 1/4″ seam. It won’t look like much of a difference for just a few blocks, but that little bit adds up over your whole quilt.

Get a custom label for your quilt!

I had some labels made for this pattern! If you want a custom Partial Dreams label with your name on it, you can get one! I order all of my labels from Melanie at Souther Charm Quilts/Meander and Make. They are great labels. You can get order your Partial Dreams Quilt label here. Just be sure to select “Partial Dreams Label” to get the one that looks like the label pictured below. Full disclosure: that was an affiliate link meaning I earn commission, but it doesn’t affect the price you pay. Use the coupon code SNUGGLEBUGSTITCHING for 10% off.

Each Week on the Blog

I’ll link to all of the other weeks near the end of each post. I will add each post here as I have them. You can also find this on the Quilt Alongs Page.

Week 1 – Gather Fabris & Cut Pieces
Week 2 – Make 6 blocks
Week 3 – You are currently at the Week 3 post
Week 4 – Make 6 blocks
Week 5 – Make 6 blocks, FREE Even Schedule for this year
Week 6 – Make 6 blocks, labeling your quilt
Week 7 – Make 6 blocks
Week 8 – Assemble your quilt top

Prize for this Week

The prize for this week is going to be a paper pattern, my Dublin Fancy pattern. This one is for US winners only due to shipping costs. If the winner is an international quilt alonger, I will send you the PDF pattern so you don’t miss out on getting a prize.

To be eligible for prizes:

– You must be following me and our sponsors on Instagram and post progress pictures for the week on Instagram by Tuesday at 5:00 PM Central Time. You must tag me @snugglebugstitching in your posts and use the #partialdreamsqal and #partialdreamsquilt.
Here are the accounts you need to be following:
@snugglebugstitching
@southercharmquilts
@benartex_fabrics

-I will announce the winner on Instagram and tag the lucky quilt alonger so that they know they’ve won. The winner will have one week to contact me to claim the prize. Any unclaimed prizes will be forfeited.