>> Well, we'd like to check that the blood samples we're storing actually 

>> about this fact, urgently.
> 

> is informed?  Would you trust a 20 quid meter from Maplin then?

My point exactly - it seems to have nothing to do with how reliable the 
device is, only the subjective feeling it gives you in your head knowing 
that "I paid lots of money for this, therefore it must be really 
reliable". Which isn't terribly scientific...

>> I'm guessing a temparature sensor that actually *works* at 
>> temparatures that low is going to cost a tad more than your average 
>> room thermometer,
> 
> Not really, thermocouples are cheap (like a fiver) and measure down to 
> below -100 degrees.

Well, maybe you have to be slightly more careful that, e.g., the 
insulator on the wire doesn't become as brittle as glass when it gets 
too cold or something.



somebody has to check it won't break or something when it gets that damn 
cold.

>> It seems 
>> the only reason for the higher price is that this is a critical 
>> device, so the suppliers know they can charge the Earth and we will 
>> pay it. We have to.
> 
> Or the fact that there is a much lower chance it will break or 
> mal-function.

Why? Do they actually *do* something different with it? Does the 
hardware itself have any actual physical differences to a cheap model? 

a several thousand percent markup, and started marketting it at a 
different market segment.

On the other hand, I remember researching printers one time. I ended up 
looking at two printers. Both Hewlett Packard. Both print at 1200dpi. 
Both have built-in network support. Both do duplex printing. Etc. But 
one printer was about 10x the price of the other. Why?

The answer is a little number hidden at the bottom of the page 
somewhere: "duty cycle". One printer said 1,000 pages/month, the other 
said 100,000 pages/month. And you know what? We ended up buying both 
printers, and one is still working to this day, the other one we 
eventually threw away because it just kept breaking so often.

In this case, it seems paying 10x the price does, in fact, get you a 
device which is *physically different*. I don't know if they use thicker 
plastic for the drive gears or what, but the more expensive printer was 
far more reliable. The cheap one is basically designed to sit in your 
house. [Actually, I have one at home. It works just fine. But then, I 
hardly ever print anything!] Put that printer in a busy office and it 
just can't cope.

>> The mass spectrometers we have here all say "for research and 
>> development only; not for diagnostic procedures" on them. I can't 
>> imagine why - it's a mass spectrometer! Either it measures masses 
>> reliably, or it doesn't. If it does, you can use it for anything you 
>> like. If it doesn't, it's a worthless piece of equipment. So... why 
>> the sticker?!
> 
> Because they don't guarantee it will work reliably the whole time.  For 
> them to guarantee that, they would need to do lots of expensive testing 
> on every unit, probably design in lots of redundant systems, use more 
> expensive components that have longer lifetimes, use better assembly 
> methods etc.

Well, you're the engineer. But I wonder - if a mass spectrometer that 

does one you *can* use for diagnostic procedures cost?! o_O

-- 
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*

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