Please – more details on the conjoint “not enough data” error!


Hello, I’ve been trying to get in touch with SG support for a few days now via live chat and email, to no avail. I really need a more thorough explanation of the “not enough data” error that can occur with conjoint survey data. I see the website gives a brief explanation of this, but it’s quite vague and I’m not 100% clear on it.


First off, it notes that this error “can happen if, in your entire data set, there is a card that was never selected” – but what exactly does that mean? Does the error occur whenever there’s a card that’s never selected by any respondent as preferred (or best/worst, depending on the questioning approach used) among the cards shown? Or does it occur whenever there’s a certain configuration that is never presented as one of the choice options over the course of the study? I cannot imagine it would be the former, because it will almost always be the case that certain options would never be selected – there will always be the random card that offers the fewest/worst features at the highest price, which will never get picked, in which case we’d get that error every time, no matter how many respondents we have.


Having this error occur when a certain combo/card isn’t generated as an option throughout the entire survey isn’t ideal either, since even for a relatively small attribute matrix it would take an unrealistic # of respondents/choice-sets to stand a fair chance of having every combination generated – but at least it would be somewhat less bleak than the former. 


And when you say it “can happen” – does that mean it will always occur in this scenario, or just sometimes (and if the latter, when/why)? I’m trying to understand under what conditions I should anticipate the error occurring or not.


I’m also trying to figure out if anything can be done to work-around this error. From the test data I’ve generated so far, I see that this error affects both the on-screen version of the report and the Excel export. There is no attribute or level utility data included in the export in this case. So am I completely stuck? It looks like I can at least still export the raw conjoint data – the choice sets shown/selected. Is my only option to find a way (in my own statistical tool) to compute the part-worth utilities from that raw data? I have no idea how to do that, so that would be a real bummer – but if that’s my only recourse in cases where this error occurs, at least it will be good to know and I can start trying to figure it out.


I would appreciate any guidance with this issue as soon as you’re able. I was excited about the conjoint module available in SurveyGizmo, and that was one of the deciding factors for me to purchase SurveyGizmo over some other options – but this is a fairly severe limitation that really hurts, that I hadn’t anticipated.


Thanks in advance for any help you can provide.

brianfeltz asked


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