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By an alternative-specific design, are the attributes of the alternatives orthogonal?

In https://www.sawtoothsoftware.com/help/issues/ssiweb/online_help/hid_web_cbc_designs_7.htm, I cannot find out whether by an alternative-specific design, the attributes of the alternatives are orthogonal? Thanks in advance!
asked Nov 17, 2016 by Marjolein Harmsen - van Hout

1 Answer

0 votes
Marjolein,

They CAN be orthogonal, yes, IF you use an orthogonal design.  Most researchers today opt for efficient designs, which compromise between pure orthogonality and pure level balance, two design criteria that are often in conflict.  So the bottom line is that if you generate your design to achieve orthogonality, your alternative specific effects will be orthogonal, too, while if you generate your design to be efficient (possibly surrendering some orthogonality), your alternative specific effects will be part of that efficiency too (again, possibly surrendering some orthogonality).
answered Nov 17, 2016 by Keith Chrzan Platinum Sawtooth Software, Inc. (52,450 points)
Thanks!
We're happy to help!
I have a follow-up question: what is the difference between say a complete enumeration strategy without attribute-specific design and a complete enumeration strategy with attribute-specific design where all attributes are common?
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