Have an idea?

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

Problem to import CBC design

We are using an external software to design the choice experiment (CBC). The result is fairly simple and is a three-alternatives situation, with generic attributes only, each attributes has four levels.

What we wish to do: the design has 12 choice situations. We want to show only 4 to each respondent, hence the design was devided into three blocs. Upon entering this part of the survey respondents should be randomly attributed a block and then answer the block's choice tasks (idealy in a randomized order).

What we did: I am not sure to understand the distiction between fixed and random task (I found the explanation in the manual not crystal clear on this point). I created a CBC exercice and told the software I wanted 12 random tasks with 3 concept per task. I then tried to import the following design (formated to Sawtooth requierment):

Version    Task    concept    tech    eff    inv    sub
1     1    1    2    4    4    4
1    1     2    4    2    3    3
1    1    3    3    1     2    1
1    2    1    4    4    4    4
1    2    2    2    1    2    1
1    2    3    3    2    3    3
1    3    1    4    1    1    1
1    3     2    3    3    2    1
1    3    3    1    4    3    4
1    4    1    1    3    1    1
1    4    2    2    4    2    3
1     4    3    4    1    1    4
2    1    1    3    4    3    1
2    1    2    1    1    3    4
2    1    3    4    2    3    3
2    2    1    2    1    2    1
2    2    2    3    4    4    3
2    2    3    4    3    4    4
2    3    1    1    1    2    1
2    3    2    3    4    4    4
2    3    3    1    2    3    3
2    4    1    3    1    1    2
2    4    2    1    4    2    1
2    4    3    2    2    2    4
3    1    1    3    3    2    3
3    1    2    4    4    2    2
3    1    3    2    2    2    4
3    2    1    4    4    2    3
3    2    2    1    1    1    4
3    2    3    2    3    1    1
3    3    1    1    4    3    3
3    3    2    4    3    2    1
3    3    3    2    1    2    4
3    4    1    1    1    3    2
3    4    2    2    4    4    1
3    4    3    3    2    4    4

I hoped this would do What I wanted; I thought the first column (version) was considered as "blocks", followed by tasks number, concepts and attributes. However something doesn't work; when I try to import this design I am getting the following error message: "The value on row 14 position 1 (the version number) is 2. The expected value is 1."

Could someone point me in the right direction? Many thanks in advance
asked Jun 26, 2014 by Albatus Bronze (545 points)
retagged Sep 1, 2016 by Walter Williams

2 Answers

0 votes
 
Best answer
With twelve random tasks and three concepts per task, the importer is expecting each version of the design to have 36 rows. Your design shown above has four tasks with three concepts per version, for a total of 12 rows per version, 36 in total across all versions. To import this specific design, you'd need to set up the CBC design to have 4 tasks per version, 3 concepts per task, and 3 versions of the design.
answered Jun 26, 2014 by Aaron Hill Silver Sawtooth Software, Inc. (9,245 points)
selected Jun 27, 2014 by Albatus
Yes, Aaron.  Indeed you need to specify that the questionnaire has 4 tasks rather than 12.  I failed to see that Albutus had said he created a questionnaire with 12 tasks in our software.  I jumped right in with our software and naturally specified 4 "random" tasks.

Still, the labels issue I pointed out is a trouble.  Need to use labels as the templates expect.
Many thanks to both of you for your comments. Indeed both problems seemed to be involved! About the design efficiency; you are perfectly right but this is normal at this stage (this is basically not our real design, but a test-design made quickly to test Sawtooth implementation. It was made with the modified federov method, which does not maintain balance).
0 votes
Interesting problem.  

I just tried it in the SSI Web v8 software.  It seems that if you provide column labels, the software is picky about what they say.  If you use the following column labels, it works:

Version    Task    Concept    Att 1 - 1    Att 2 - 2    Att 3 - 3    Att 4 - 4

Also, please note that the design efficiency for your custom-built design is very poor.  The design lacks level balance (for example level 2 of attribute 4 occurs 3 times, but levels 1 and 4 of attribute 4 occur 12 times).  Maybe you have a specific reason to do this design...but it looks fishy to me.
answered Jun 26, 2014 by Bryan Orme Platinum Sawtooth Software, Inc. (154,305 points)
...