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Stoelting CPSpro -- any opinions?

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Author Topic: Stoelting CPSpro -- any opinions?
Dan Mangan
posted 05-30-2012 08:25 PM Click Here to See the Profile for Dan Mangan Edit/Delete Message
I'm looking to upgrade from my LX4000 in the not-too-distant future. Stoelting's CPSpro looks pretty good on paper. If anyone has real-world experience with the CPSpro, I'd very much appreciate hearing their opinions of the instrument.


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Barry C
posted 05-31-2012 09:28 AM Click Here to See the Profile for Barry C Click Here to Email Barry C Edit/Delete Message

I've had it since it came out - as a beta tester. I would recommend it to anybody looking for a new instrument. Like the other manufacturers, the folks at Stoelting are very responsive. If the software doesn't do something you want it to do (within reason, of course), let them know and you'll soon see a change.

As far as data quality goes, I couldn't be more happy. I get good signals from most everybody. As a rule, I don't see those plunging EDAs you mentioned elsewhere. Some people have EDAs that tend to drift downward, but they're the exception and not the rule.

The beauty is that the CPS records the data and then redisplays each channel in its own "swim lane." That way, everything fits nicely on the screen. Any sensitivity adjustments you make while recording are only for your viewing pleasure. It doesn't change what's coming in or how it's redisplayed. You can zoom in, increase sensitivity, etc, for scoring purposes, but you never lose anything. The editing features are also nice. If you have a finger movement in the cardio, for example, you can ignore it to score it by hand, but the computer "sees" the increase as just that and considers it a large reaction. You can edit it out with the CPS (without altering the original data - it's all tracked and reversible), and then you can use the algorithm(s) to give you a second set of eyes.

(I know the thought of editing scares some people, but the Utah studies almost always edited as part of the process. It's usually not many cases, but it happens. Of course, if the manufacturer smooths or filters (a form of editing) behind the scenes, we're okay with that, but if the examiner does it....)

I think their most recent activity sensor is about as good as it gets. I like other instruments too - don't get me wrong - but I think Stoelting is onto something with the current activity sensor. I can almost see eyeblinks. If I have time, I'll see if I can post a comparison and show why I like it.

Their software has come a long ways since CPS-II, but I was happy with that system too. It wasn't the flashiest system, but it recorded good quality data. The PRO is the best of both worlds, all the bells and whistles and good data quality. (I'm no engineer. I can only speak from a user's perspective.)

My best advice: attend a seminar where they are all present and look, test, ask questions, etc. Be careful of what one vendor says of another. I've heard lots of complaints that some of them provide information (about others) that is inaccurate. I'm not saying it is or it isn't, but it's one more reason for you to put on your investigator hat and check everything out. In the end, there are pros and cons for everything. You have to weigh them and decide. Some differences are like Chevrolet verses Ford. Others may not be. You'll have to decide.

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Dan Mangan
posted 05-31-2012 10:22 AM Click Here to See the Profile for Dan Mangan Edit/Delete Message
Thanks a million, Barry. That's exactly the kind of input I was looking for.

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posted 05-31-2012 10:26 AM Click Here to See the Profile for rnelson Click Here to Email rnelson Edit/Delete Message
Re data editing and interpolation.

It does not bother scientists much at all. Neither does some filtering as long as it is accounted for. Editing data can reduce the need for more complex statistics (with less power) in science when balanced designs are used. In polygraph it may mean fewer inconclusive results.

Normal protocol is to account for editing, interpolation, or replacement of data with average values, by calculating and reporting the proportion of data that was edited/interpolated/mean-replaced.

Less than 2% is generally no concern. Probably same with 5%. Between 5% and 10% is worth paying attention to the difference in scores that would result without editing/interpolation/mean-replacement. If more than 10% of of data is edited that would be a bit of a concern. These are, of course, arbitrary and blunt general guidelines.



"Gentlemen, you can't fight in here. This is the war room."
--(Stanley Kubrick/Peter Sellers - Dr. Strangelove, 1964)

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Barry C
posted 05-31-2012 11:04 AM Click Here to See the Profile for Barry C Click Here to Email Barry C Edit/Delete Message
I concur.

For some reason, I can't log into photobucket from here, but I created a low quality jpeg or pdf to show the differences in activity sensors - and the reason I like what I'm seeing now. Unless somebody else can do it, I'll try to remember to do it later tonight.

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