The wrong choice of yarn can undermine a tester's results before they even start. Making sure your testers pick the right yarn saves you and them a whole lot of pain and time.
Tell me if any of this sounds familiar:
"
I've finished Row 5 but my work is much wider than it should be."
"
I just can't seem to meet gauge. I don't normally have issues with my tension but this time I'm way off."
"
Oops! I seem to have bought the wrong type of yarn. I need to start over. I might miss the deadline."
"
I thought I had the right yarn but just realised that it's much thicker. Can I still use it?"
It's not just a matter of frustration from having to start over. If your tester doesn't have the right yarn in their stash, they'll have to purchase more from their local craft store or order it online. Which means further delays, and there might not be enough time left to comfortably finish the test. Especially if the tester started a bit late in the first place.
Leader's intent
I'm a strong advocate for the principle of Leader's Intent. It's the concept of sharing
what you're trying to achieve and
why, so that if there's any confusion as to
how, people will have all the information they need to make the right choices.
Unfortunately, that won't work here.
Even if not explicitly spelled out, the intent is generally pretty clear: the pattern would have been designed with a specific yarn weight/thickness in mind, so you'd want your testers to replicate those same conditions when testing your pattern. Otherwise the test results will not mean much. Size will almost certainly be off, the stitch texture will change, the item will look different, etc...
Great testers don't need to be told this. They either already know it, have figured it out on their own, or will speak up early if in doubt. You don't have to worry too much about them.
Similarly for average (sorry, not trying to be snide here) testers. They'll be OK with a simple note to the effect of:
"You don't have to use the same yarn or colours we used as long as your substitute has approximately [such and such] metres of yarn per gram. Let us know if you need help with this."However, Leader's Intent fails when it comes to people who tend to not pay much attention to detail, glossing over instructions or outright ignoring them.
These would be the testers who regularly seem to be involved in some kind of issue. They're the ones who don't send you proper feedback (
"All good. Great pattern!"), miss deadlines (
"Oops, forgot I was meant to send it yesterday!") and repeatedly ask questions for which you've provided answers to twice or three times already (
"Where can I get the pattern from?").
(Side note: This is why you need to curate your testers, and a pool can help with that. Learn all about
The Benefits of Having a Tester Pool)
So Leader's Intent is not the most effective way to guarantee success in this situation. It's a good start though, so you should definitely add a note with some substitution instructions (feel free to just copy the one above) for anyone who might be genuinely confused by the whole thing.
To be clear, yarn substitution can indeed be quite confusing. It can also get quite complex in specific situations, and whole books have been written about fibre content, structure, texture, drape and all that. You almost certainly won't get anywhere close to needing all that. If you do, then that's a different conversation altogether!

Make yarn requirements clear
An obvious one, but it bears pointing out: make your yarn requirements clear.
State what kind of yarn you need and approximately how much of it, per colour. More on this further down.
Repeat this information at every step of the way, beginning from the test call. Include it with any testing instructions, keep it easily accessible for them, and make sure it accompanies your pattern.
If you require a specific yarn brand or product line, or if you need specific colours, make sure you also say that upfront with the test call.
Specify yardage in units of length, possibly accompanied by weight
Be careful if you want to indicate how much yarn they'll need in terms of weight. By which I mean grams/ounces, not the weight category (such as Aran, DK, etc...)
It's OK if the weight is accompanying the length, but it might lead to some confusion if it were to be on its own.
Length is constant across all brands, weight categories, and fibres. 1 metre is always going to be 1 metre. It looks the same every time. On the other hand, weight is conditional on the yarn's material and thickness. 1 gram does not always translate to the same amount of yarn.
If there are calculations or any weighing that needs to be done, they'll have to happen either way, but at least "
You'll need 100m of yarn" is easier to visualise than "
You'll need 40g of yarn."
I would recommend including both. You can provide the weight in brackets immediately after the length measurement:
You'll need 100m (40g) of yarn.
Avoid weight categories like the plague*
* Unless you're really confident in the reliability of your testers. And still, it should always be accompanied by more information.How melodramatic of me.
I stand by it.
Unless told otherwise, some...dare I say, most...testers will just read Aran and pick a yarn that says Aran on the label. It's a recipe for disaster. Quoting from Ava & Montague's
A Guide to Yarn Substitution, with their permission:
[There is too much variation] within yarn weight categories. Each weight represents a range of yarn thicknesses. These ranges are broad, not precise and, more importantly, not universal. Each yarn brand/maker might have their own way of categorising their yarns. To make matters worse, different fibres have different densities. So, gram for gram, two yarns of equal thicknesses might have completely different lengths.What I would recommend is to only include the weight category as a general indicator of the yarn's thickness. It should be preceded, or immediately followed by, a very explicit and much more prominent yardage ratio of your desired yarn.
The yardage ratio is the length of yarn per gram/ounce. If you're unfamiliar with this concept, you should definitely check out Ava & Montague's article linked above.
Your testers should be using a yarn which is as close to this as possible, ideally with a difference of less than 0.25 metres per gram/yards per ounce.
This ratio should demand more visual attention than the weight category, which should only be included for convenience. Specifying that the required yarn happens to be, let's say, Aran, should only serve as a suggestion to start searching through Aran yarns, to then be able to narrow the search down to a yarn that has the required yardage ratio.
So how would all of this seemingly complicated concept actually translate in a pattern or test call?
If you're using a tabular format, such as in a pattern booklet, you can give prominence to the yardage ratio by:
- specifying the weight and length of the skein immediately after the weight category
- including yarn substitution instructions. The fact that the yardage ratio is in a separate line highlights its importance. Additionally, it makes sure that it can't be accidentally missed amongst the rest of the figures and measurements.

If the context is more textual in nature, such as in test instructions, you can mention the weight category as an aside, then include explicit yarn substitution instructions. Offering assistance with this can go a long way in ensuring testers speak up if they're confused and conveys the importance of them getting this right.
Caveat #1 - Proper yarn substitution does not replace the need for a gauge swatch if that's something you need in your pattern. Gauge deals with other, more nuanced issues as well. It helps your testers find the right tension and allows them to compensate by systematically making minor adjustments. But if they're using the wrong type of yarn, the discrepancies will be beyond the scope of checking for, and meeting gauge.
Caveat #2 - There is a very small but non-zero amount of testers who would ignore absolutely anything you decide to list and pick any yarn they want. Even something as direct as a weight category, if you were to include it. First off, you should expect to receive cries for help when their sizes don't match up. Secondly, this is a symptom of a much bigger issue (as described earlier in this article) which tester curation can help solve in future tests. To help address it in the immediate term, where some of your testers are new to you and you don't yet know what to expect, see the
Ask them to check in at the start section below.
Do not mention the quantity of balls or skeins
It's mostly a matter of too many numbers and assumptions.
Let's say you need 100m of yarn, and that this specific line of yarn comes in both 100m and 200m skeins. Are you going to say that they'll only need 1 skein? They'll need a bit of wriggle room, right? So maybe 2 skeins then? Is it too much? Wait, is it two of the 100m skeins or the 200m skeins? What if there's another size that you're not aware of? Better specify what length of skein we're talking about, just to make sure.
What about yarn substitution? Do we really want them to have to look up the yarn's weight and length in order to calculate the ratio? What if they look up the wrong product, or there's a mistake on the website? So better put down those numbers as well! Once we're at it, just tell them the yardage ratio.
But then, if they're substituting their yarn, what purpose does including the number of skeins serve?
And on it goes.
Ultimately, it's just an extra number which doesn't really add any value. It can only get in the way of the important values and potentially be misinterpreted, causing more confusion.
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Offer your help
If they're in doubt, help them out!
Tell them that they can contact you at any time if they need your help in choosing a suitable substitute. Some might not know how to do this and would appreciate your assistance. It would also be a good opportunity to show them how to calculate a yarn's yardage and compare it to the pattern requirements. Perhaps refer them to
a handy guide to yarn substitution.
You'll be teaching them an essential skill they can use in any pattern they make in the future, including ones they might be testing for you!
These might sound familiar:
- "Is this yarn good?"
- "Can I use [XYZ yarn] for this shawl?"
- "I don't have any Aran. Is DK good?"
I know, I know. You've communicated your yarn requirements a thousand times already.
You've highlighted them, written them down in flashing colours, stuck a bow and hat on them, made them jump up and down and do a little dance.
And still there's always someone who asks what yarn they need to use.
Facepalm. Double facepalm. And...
You should bite your tongue and help them.
Whether the confusion is genuine or not does not matter. Remember, pride goes before the fall. Placing blame and being right does not help here. You need to be effective. It only takes a minute to solve this for them. It will be the umpteenth time you've done this, yes, I know. And it will save you and them a lot of time and trouble.
Ask them to check in at the start
Bring it all together by requiring them to confirm the yarn they'll be using right before they start.
This is probably the most effective thing you can do. Even if you haven't done any of the above, you can catch and mitigate against so many issues by asking your testers to do this one simple thing for you.
You can (and should) tell them about this in advance, but specify that they need to check in with you just as they're about to start the test. They don't necessarily need to wait for your acknowledgement before starting, although you should definitely reply back, even if everything's OK.
Asking them to check in with you has two major benefits:
You can manually confirm that the yarn they're using is correct. It takes a minute, and seems inefficient in the short term, but it saves you time and heartache down the line, which makes it, in fact, efficient. Also, extremely effective.
It lets you keep track of who is doing what by when. You know that those who've checked in with you have started working on the pattern, or are about to. At the very least, they've read and followed your instructions, which is a very good thing. More points to them. Conversely, you can follow up on those who do not check in after a certain number of days from the start. This doesn't mean that something's wrong, so make sure you have the correct attitude. However, if there is something that requires your attention, you'll be able to catch it early on and hopefully be able to fix it.
Asking your testers to check in is a small, but powerful, example of how to use simple milestones in your testing workflow. This is a concept which I'd like to expand on in future articles.
Start taking action
In summary:
Always make your yarn requirements clear, as early as possible, and as often as you can.
Prioritise length over weight (as in, grams and ounces) and be very careful when mentioning weight categories. Do not include the number of balls/skeins.
Most importantly, ask them to check in with you at the very start.
Always offer your help and then be present for your testers. You'll need lots of patience. If you feel like you're running out and need to vent, I'm just a message away. I got you! Just make sure to keep your frustrations out of your tests to keep them running smoothly!
Tell me your stories
How has yarn substitution affected your pattern tests in the past? How are you handling it now?
Share your story in the comments section below.
Maybe you'd like to share a frustrating conversation?
Or perhaps you'd like to celebrate the wonderful ways you've seen testers help each other choose a suitable yarn.
I'd love to hear about it!
Stephen
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