The testing foundation “Stiftung Warentest” uses strange methods to test mattresses

Representation of an open letter to Stiftung Warentest about the mattress tests, even today still a current one, although the letter dates from 2012.

When testing mattresses, Stiftung Warentest determines the hardness, permanent elasticity, moisture transport, the quality of the cover fabric, chemical vapours and much more. But when it comes to lying characteristics, the testers find themselves on unsafe terrain. This becomes particularly clear in the mattress test in November 2012, because in order to evaluate the lying characteristics, the conditions for this must first be defined.

And here lies a big shortage. Also in the last test only a few text passages can be found: The buttocks should sink in slightly in the supine position, the mattress should support the back in the cross and in the lateral position the spine should lie straight.
In the mattress test, the testers previously assumed the body proportions of an average person, with the requirement that the mattress must adapt to these body curves. The body should sink into the mattress (but not too deep) and be supported by it. In addition, as little pressure load as possible should occur when lying down. So far, so vague.

But now it is only the lying person who can decide whether he or she lies well or not, or whether he or she feels well or not. Whether this formal and undefined concept of different support of body sections really makes an average person feel comfortable on a well-rated mattress is quite possible, but not likely.

The perception of the body and the human well-being do not result from the defined support of his parts, but rather from his very personal way of using muscles, ligaments and fascia, i.e. from the inner tension and tensenesses and thus ultimately from the individual character of movement. Every human being has a very personal and unique physical tension structure, which corresponds only conditionally with the outer body forms.

In addition, there are the special preferences of people. Some like a mattress with a soft surface, but firmness inside, for others it’s the other way around. Some like a powerful elasticity, others don’t like it swinging at all. Some want pressure on the buttocks, others don’t want to feel at all or even sink into the mattress.

When it comes to feeling and taste, it is not possible to make specifications with metrological instruments, i.e. to determine an optimal mattress for “the human being”.

Stiftung Warentest seemed to have come closer to this insight. Thus in January of this year it was still determined that mattresses are a matter of taste and that there are therefore only three ways to find the right mattress in the variety of the offer: “try out, try out and try out again”. We agree with that.

But what does the foundation do for the latest mattress test in November 2012? The testers are surprising with the statement that they are now testing the mattresses even more critically. Instead of refraining from the requirement to determine the lying comfort of a mattress generally, they now go even further into detail with their measuring technology.

The testers have now discovered that there are people with very different body shapes and that these should not be lumped together, which means that people with their different bodies cannot lie equally well on one and the same mattress.

So Stiftung Warentest has divided people into four body shapes: the heavy cupboard-shaped man, the big strong man, the small pear-shaped woman and the small light woman.

The question arises as to why mattresses for different body shapes have not existed for a long time and, conversely, they come to the surprising conclusion that there can actually be no “universal mattress”.

How did Stiftung Warentest come to the conclusion that such a thing could exist? As far as we know, no manufacturer with such a claim has appeared so far. On the contrary, so far whole series of different mattresses have always been offered.

If Stiftung Warentest will continue with this somewhat curious division of the human body into four basic forms and continue to carry out its measurements accordingly in the future, manufacturers will have to act and see that they categorise their mattresses accordingly. Because no manufacturer can afford to fail the tests in the long run. So it may soon be offered the mattress type pear, the mattress type cabinet and possibly also the mattress type apple for spherical people.

However, we believe that Stiftung Warentest has maneuvered itself into the sidelines with this procedure.. In principle, this step towards ever greater differentiation cannot achieve the goal.

Even the most sophisticated measurement technology cannot capture the human being with his or her needs. The claim to determine the right mattress from the curves, weights and proportions of the human being on the one hand and the technical data of the mattresses on the other hand, treats the human being as a trivial machine and ignores the complexity of the individuals. Even four specially shaped people and five experts for “comparative subjective assessments” can only judge for themselves and not for others.

With this change to the “even more critical examination”, many of the earlier results are per se obsolete or incorrect. While in January 2012 it was still said “Expensive is not worth it”, only the expensive models performed well in the repeated test of the same mattresses.

We at Stiftung Warentest miss a method-critical view beyond the engineering trade and a more self-critical attitude.

Back to the latest test

Since the testers have now found no mattresses for the four body types they have specified, further testing continues undaunted. Only that now a pear-shaped woman, a cupboard-shaped man, a heavy man and a small woman are also used for testing.
To everyone’s astonishment, a mattress that seems to be suitable for all body shapes is found during this test in complete contradiction to the preliminary consideration. A miracle mattress? Has Stiftung Warentest mismeasured or is it so presumptuous to measure something that cannot be measured? We don’t know. This unexpected result is in any case not questioned and the embarrassment of this process is not even perceived as such.

We also find it embarrassing that for the evaluation of the lying quality in the lateral position again the model of the straight lying spine is used as a criterion. This “intervertebral disc model” s apparently not to get out of their heads. It is not explained why the spine should lie straight in the lateral position. The original assumption that the intervertebral discs can only refill with fluid when the spine is stretched has long since been refuted by pressure measurements. (Spine, Volume 24, 199 “New in Vivo Measurements of Pressures in the Intervertebral Disc on Daily Life”, see also the summary on our website ).

The “intervertebral disc model” has no verifiable legitimation – except that it serves to dupe customers. It is a pure marketing tool. And Stiftung Warentest can also be exploited instead of questioning its own methods.
Our verdict on this mattress test: inadequate.

Addendum: Surprisingly, one of the test providers replied to our letter. Unfortunately, the answer was very formal and technically justified, without going into the core of our letter.

Published by on 20.11.2012


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