Have an idea?

Visit Sawtooth Software Feedback to share your ideas on how we can improve our products.

Unspecified error when estimating alternative-specific CBC

When I use the menu to analyze alternative-specific design CBC I find in the setting/constraints a long list of very odd looking constraints with many terms like 'UNKNOWNLEV_2' and also levels that are from a previous design rather than my latest version. The "prepare for estimation" works and results in a "ready to estimate" report but after that when I click estimate immedeatly a popup shows:
"the following error has occured during estimation: [nothing is specified]"
This happened during testing of my survey and I can change everything yet before I go live. What do I need to fix?
asked Jul 7, 2014 by alex.wendland Bronze (2,080 points)
PS: I opened the study file in a text editor and found that some attribute and label names where still present that I had replaced a while ago. I had even overwritten the design after altering the labels and levels. Are the old values still active in the prohibitions maybe and that is why the constraints include strange levels?
PPS: I removed the complete alternative-specific CBC exercise and the old labels disappeared from the study file. Then I rebuild the alternative-specific CBC exercise including the prohibitions. Then I generated respondents and tried the estimation again. This time the list of constraints was empty. Shouldn't there be some constraints in a alternative-specific CBC estimation or is all the information in the design file itself or in the response data?
PPPS: I found that the constrains in the settings were specified in a previous test estimation and didn't adapt to the changes in levels that I had done in the meantime. I guess my problem is solved for the time being. I posted a followup question, however, where I need some pointers on how to prep my excel simulator to reflect the alternative specific design in the model specification.

1 Answer

0 votes
Best answer
I think this was a bug that is either fixed or is set to be fixed in the next maintenance release.  If you modified the estimation settings for HB, and then you went back and changed the attributes and levels in the design, those constraints stayed but weren't referencing anything and would cause a problem.  Deleting the constraints or hitting the button to reset to defaults should fix an issue like this.
answered Jul 7, 2014 by Brian McEwan Gold Sawtooth Software, Inc. (39,170 points)
selected Oct 8, 2014 by alex.wendland