
Are women really better than men at furniture assembly (as IKEA claim)? - nkurz
http://digest.bps.org.uk/2015/12/are-women-really-better-than-men-at.html
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stenl
Published in a shitty journal (Impact Factor: 1.3) with n = 10 per group. Also
relevant: most psychology research published in high-ranking journals cannot
be reproduced
([http://m.sciencemag.org/content/349/6251/aac4716](http://m.sciencemag.org/content/349/6251/aac4716)).

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MollyR
Where do you get impact factors for psychology journals ?

~~~
dietrichepp
They're calculated every year. It is merely the average number of times an
article in the journal will be cited.

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frossie
_In terms of time taken, the men took 22.48 minutes with instructions, on
average, [...] compared with the women taking 23.65 minutes with instructions,
on average,_

I [female] would lose 5% in time over a median guy just by slower
screwdriving, never mind cognitive performance. This is why I assemble Ikea
furniture with a power screwdriver - it's not easy work if you're not used to
it.

~~~
JoeAltmaier
Don't they use those screw-slot devices that you just turn a quarter turn and
they lock? So maybe no difference there.

~~~
alricb
Yes, but these connectors also include a stud you need to screw into a hole.

In this case though, the Udden trolley [1] is made of steel and uses machine
screws, but none of these quarter-turn connectors.

[1]:
[http://www.ikea.com/aa/en/catalog/products/10176471/](http://www.ikea.com/aa/en/catalog/products/10176471/)

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bewaretheirs
One thing that significantly improved my IKEA-assembly skills:

For its cross-head screws, IKEA generally uses Pozidriv rather than Phillips
screws. They're subtly different - but if you use a Phillips driver on a
Pozidriv screw (or vice versa) you tend to wreck the screw head. Use the IKEA-
sold screwdriver (or get a better Pozidriv set).

~~~
mjevans
Why. Why does this even exist? It's bad enough that we aren't using hex-head
but to have two different ones that look so similar an average person can't
tell them apart without instructions, AND which not only fit in each other's
sockets but wreck them?

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alricb
One thing to note is that the trolley they assembled is made of steel and
assembled with machine screws and a funny stud/"nut" combination. People's
experience with your typical dowel/screw/quarter-turn connector wooden
furniture might not have helped them that much.

However, because the trolley is pretty light (~14 kg) and its fasteners don't
require much strength to screw in (vs. the larger screws in wood furniture),
it might have mitigated the strength difference between men and women.

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mr_luc
The IKEA person may have stated the claim in a broad way, but as a thought
experiment, is it possible that they're correct despite this study?

> on average, men tend to outperform women on spatial skills, which you'd
> expect would be relevant to furniture construction.

Could it actually be irrelevant? There's a case to be made there.

Is time of construction, _as measured in this study_ , actually important to
IKEA? If the reasons for faster male performance in this study are down to
(possibly genetic) advantages in dealing with _new_ spatial problems, or a
cultural factor like males having on average more exposure to various kinds of
construction, which manifest in them showing a (slight) edge in constructing a
brand-new design, well ... due to the manufacturing effect, that advantage
should disappear!

With practice, false starts and misunderstandings will go away. At that point,
what matters to IKEA? Probably, 'perfect' assembly. It's possible that IKEA
found that women showed lower defect rates than men. That would make sense
given that they called out that women followed the assembly instructions more
closely.

IKEA's claim was simply that 'women are better at assembling flat-pack
furniture than men,' and this study wanted to see if the known male edge in
understanding spatial problems extended to flat-pack furniture. It apparently
does, but that doesn't necessarily mean that women still might not be
'better,' at least from IKEA's point of view.

~~~
TheOtherHobbes
The results showed that men were rated higher for construction quality.

But I think it's interesting that it takes around 25 minutes to put a trolley
together, and it's hard to get a perfect score for construction quality.

The design of the product has a lot more influence on time/quality than
gender. And it looks like the design could be improved.

I always assumed that flat pack furniture was similar to cheap commercial
furniture without the construction costs, and with lower shipping costs. But
it's assembled using the same standard techniques.

Is it possible to design good furniture with much simpler/quicker assembly
techniques? Maybe not. But if it is, perhaps there's a commercial opportunity
there.

~~~
larrik
In my experience, the techniques can be quite different.

Flat-pack furniture needs to buildable by just about anyone, using tools that
they can be expected to have (screwdriver and hammer only, in practice) or you
are willing to include (allen wrench). On top of that, it's usually also
designed to be disassembled as well to a degree, since otherwise mistakes and
can be permanent and costly. Also, and perhaps most importantly, flat pack
furniture almost never uses glue, which is often a very important component of
factory assembled furniture.

~~~
logfromblammo
Factory assembled furniture often makes use of highly specialized and
expensive equipment that most people don't even have access to.

For instance, a wood steamer, to bend the back of a chair into a curve,
followed by a few days of immobilizing and drying the piece. This sort of step
is only cost effective when you are building hundreds of chairs.

Or there might be staples from a staple gun, or springs that can only be
installed with the help of a power tool.

And, as already mentioned by parent, most factory-assembled wood furniture
nowadays uses dowels or wafers and wood glue. The resulting join is _much_
stronger than twistlock connectors in particle board.

But you can fit more flat-pack chairs in one cargo container, which is about
the only reason they even exist. If you are confident in your assembly
abilities, a bottle of wood glue, clamps, and a framing square will produce
better results on particle-board furniture than following the instructions as
written. If not, you'll make a mess and ruin your furniture. And honestly,
sometimes you just need something that's good enough to do the job, for $20,
that you can just discard the next time you move.

~~~
larrik
Thanks for validating and expanding on my post with more detail.

I personally wouldn't try using glue on flat-pack furniture, though. For one,
the pieces are generally finished there they connect, which means you are
gluing to a lacquer on at least one side (possibly both!), and wood glue
really wants a porous surface like unfinished wood. Another reason is that
much flat-pack furniture (less so Ikea) is super cheap particle board that
simply isn't strong enough to support the much weight from its surface like
you would force it to with glue.

When used properly, however, wood glue is indeed shockingly strong.

~~~
logfromblammo
You have to fit the pieces, mark the edges, score the veneer, and remove the
strip. It's not usually worth the effort.

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jazzyk
IKEA's furniture comes with quirky instructions (no words, just graphical
"sign" language, to avoid translating into tens of different languages). Women
may be a bit more patient with figuring out what it means (more empathy, less
testosterone)

~~~
krzyk
IKEA instructions are not quirky, they are actually quite good. Compare them
to intructions provided by to some no-name brand or any other smaller
furniture provider - those are quirky (and low quality, photocopied paper).

~~~
dogma1138
They are quite annoying but most of the no-brand Chinese furniture I ordered
from amazon came with better instructions, the English wasn't stellar in some
case but it had all the dimensions of every part including the angles in the
instruction manual, they've also always used standard nuts and bolts and
specified the exact type including diameter, torque and thread count.

IKEA used non-standard parts in most cases they are "easier" to assemble in
some cases since they are always designed to be pretty much with only a
standard flathead/philips driver but GL getting replacement bolts if they
missed one in the packaging or you lost one during assembly or disassembly, so
yes I rather have a cheap photocopier paper with the measurements and part
part numbers on it than the graphical IKEA instructions because I can just buy
missing or broken parts or make them myself when needed rather than chug the
entire thing into the garbage 3-4 years down the line.

My grief with IKEA is that these days it's pretty much neither here nor there
unless you are in luck and something is on one of their 80-90% discount sales
then the cheap stuff will be of horrid quality sometimes being even worse than
no-brand crap from Amazon or you nearest big-box while their expensive stuff
is in the price range of the big department stores, furniture boutiques and
depending on the country even custom made furniture (My parents have had
several closets and a study custom made fitted and assembled for cheaper than
IKEA's mid and upper range prices and it looked 100 times better). Not to
mention that IKEA is just horrible when it comes to shipping and customer
support compared to both Amazon and large department stores.

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logfromblammo
I might also test these hypotheses:

 _People improve (or degrade) their performance at objectively measured tasks
when told they should be better (or worse) at doing them than others._

 _The magnitude of the above effect differs between men and women._

In other words, repeat the experiment, this time (falsely) telling the test
subjects that, according to prior experimental results, female assemblers
should be able to complete the task faster and more accurately than males. See
what happens.

If tested and confirmed, the effect would be similar to the placebo effect in
medical trials.

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larrik
"When mental rotation ability was factored out of the analysis, there was
still a sex difference in time taken to construct the furniture, but the sex
difference in the accuracy of the construction disappeared, which certainly
suggests that one reason the male participants may have outperformed their
female peers is because they tended to have superior mental rotation
abilities, likely making them less dependent on the visuals in the
instructions."

How would a researcher factor out mental rotation ability after the fact?

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bonobo3000
Glad to see this! Women often tell me i "finish screwing way too fast". I now
understand they are simply jealous of my potential as a furniture assembly
man.

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JoeAltmaier
The 'fitness function' they used was time only. Doesn't consider/weigh the
cost of bad assembly (trolley falls on your kid spilling boiling tea
everywhere) etc.

I can assemble that trolley in 5 seconds - throw the parts in a pile, Done!
Some errors of course.

~~~
andyl
The study did look at build quality.

"In terms of construction scores (from 1 to 10 where 10 represents a perfectly
built trolley), men averaged 8.9 with instructions, 7.6 without; the women
averaged 7.5 with, and 5.7 without."

~~~
JoeAltmaier
Ah. I skimmed too quickly. So, a clear advantage to the men.

Funny the article ends up with some pap about 'men and women can benefit from
clear instructions' where the study showed that to be false.

~~~
danielsamuels
But it didn't show that to be false. The comment you replied to proves it.

~~~
JoeAltmaier
But men gained only a few percent improvement with instructions...

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xyzzy4
There's no way that women are better. The implication of that would be if you
have a furniture assembly business of female employees versus male employees,
all other conditions being the same, the female business would be more
profitable. Which wouldn't make any sense.

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Kluny
Nothing about that statement makes sense. For one thing, furniture assembly is
normally paid for by piecework. Each assembler's personal speed level makes no
difference. If furniture isn't getting built fast enough, more assemblers are
hired or existing assemblers work more hours.

"All other conditions being the same" \- a business operated only by women
will be very different from one operated only by men. All other conditions
will not be the same. There will be different assembly line procedures,
different levels of teamwork and communication, different expectations about
how much work must be done and how many items must be sold, different customer
interactions.

"The female business would be more profitable. Which wouldn't make any sense."
This statement is meaningless.

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xyzzy4
_Each assembler 's personal speed level makes no difference. If furniture
isn't getting built fast enough, more assemblers are hired or existing
assemblers work more hours._

Personal speed makes a lot of difference. For example, if the speed was zero,
nothing would be built. It would cost your business more money if you have to
pay people for more hours. So having male assemblers would cost more if they
are worse at it.

~~~
Kluny
See the part re: piecework. Furniture assemblers are not paid by the hour.
They are paid by the number of items they build to an acceptable standard.
Assemblers whose assembly speed is zero don't get paid. Unless your furniture
shop exists only in a hypothetical math universe at the extreme end of a
graph, there will be assemblers available who can build furniture adequately
fast for the company to stay in business.

