Blog Archives

The MaxDiff Killer: Rank-Ordered Logit Models

February 27, 2013
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Compared to MaxDiff (Sawtooth Software), ranked-order logit modeling:simplifies data collection without needing additional software to generate experimental designsreduces respondent burden making the task easier and seemingly ...

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When Discrete Choice Becomes a Rating Scale: Constant Sum Allocation

February 19, 2013
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Why limit our discrete choice task to next purchase when we can ask about next ten purchases?  It does not seem appropriate to restrict choice modeling to one selection only when repeat purchases from the same choice set&n...

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Incorporating Preference Construction into the Choice Modeling Process

February 15, 2013
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Statistical modeling often begins with the response generation process because data analysis is a combination of mathematics and substantive theory.  It is a theory of how things work that determines how we ought to collect and analyze&n...

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Reducing Respondent Burden: Item Sampling

January 22, 2013
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Reducing Respondent Burden: Item Sampling

You received confirmation this morning.  Someone made a mistake programming that battery of satisfaction ratings on your online survey.  Instead of each respondent rating all 12 items using a random rotation, only six randomly selected i...

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If SPSS can factor analyze MaxDiff scores, why can’t R?

January 17, 2013
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If SPSS can factor analyze MaxDiff scores, why can’t R?

Answer:  The variance-covariance matrix containing all the MaxDiff scores is not invertible.  R tells you that, either with an error message or a warning.  SPSS, at least earlier versions still in use, runs the factor analysis witho...

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Warning: Sawtooth’s MaxDiff Is Nothing More Than a Technique for Rank Ordering Features!

January 14, 2013
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Sawtooth Software has created a good deal of confusion with its latest sales video published on YouTube.  I was contacted last week by one of my clients who had seen the video and wanted to know why I was not using such a powerful technique for me...

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Item Response Modeling of Customer Satisfaction: The Graded Response Model

January 8, 2013
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Item Response Modeling of Customer Satisfaction:  The Graded Response Model

After several previous posts introducing item response theory (IRT), we are finally ready for the analysis of a customer satisfaction data set using a rating scale.  IRT can be multidimensional, and R is fortunate to have its own package, mirt, with excellent documentation (R.Philip Chalmers).  But, the presence of a strong first principal...

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PLS Path Modeling with R: A Comprehensive Tutorial by Gaston Sanchez

January 6, 2013
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PLS Path Modeling with R: A Comprehensive Tutorial by Gaston Sanchez

Gaston Sanchez has just published an online pdf of his new book PLS Path Modeling with R.I have been using Gaston's plspm r package for a couple of years to analyze marketing data.  I started when I needed to test a path model in wh...

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Searching for Structure underlying Customer Satisfaction Ratings: Item Response Theory through the Back Door

December 30, 2012
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Searching for Structure underlying Customer Satisfaction Ratings: Item Response Theory through the Back Door

Variations on a Theme of Negative Skew and Positive ManifoldNo one familiar with research on customer satisfaction expects to find uncorrelated ratings or symmetric distributions centered toward the middle of the rating scale.  There are forces at work that structure the means and correlations among the items from a customer satisfaction questionnaire.  On the one hand, unsatisfied customers churn,...

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Making Friends with Multicollinearity

December 18, 2012
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Not every system of independent variables can be decomposed into separate components, each with its own unique contribution.  Sometimes our individual variables behave “as a unit” and thus become so entangled that we cannot say where the effect of one variable begins and the effect of another variable ends.  In such cases, it might be best to ignore the ...

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