Blog Archives

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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Clarifying a Previous Item Response Theory Link

December 11, 2012
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I wanted to thank those of you who have emailed and commented on my last post and its Link to Item Response Theory Presentations Using R.  In the Psychometrics Centre website, it is not until Topic 7 called Unidimensional IRT models for binar...

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Link to Item Response Theory Presentations Using R

December 6, 2012
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After my post on item response theory,  a number of you have asked for links to applications that provide R code.  As I noted in that post, a good deal of work is being done in an area of research called patient-related outcome measurement (P...

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How Microsoft Can Use Windows 8 to Dominate the Tech Industry

November 9, 2012
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How Microsoft Can Use Windows 8 to Dominate the Tech Industry

Windows 95 transformed the PC software market and established Microsoft as the dominant player.  Can Microsoft do it again?  Can it use the release of Windows 8 to elevate its entire brand image?  More importantly to some of us, can Microsoft use statistical modeling to help it achieve its goal?Of course, the answer depends on what you mean by...

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A Brief Tip on Generating Fractional Factorial Designs in R

October 1, 2012
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A number of marketing researchers use the orthoplan procedure in SPSS to generate fractional factorial designs.  It is not surprising, then, that I received a number of questions concerning the recent article in the Journal of Statistical Software by Hideo Aizaki on “Basic Functions for Supporting an Implementation of Choice Experiments in R.”  To summarize their issues,...

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Item Response Theory: Developing Your Intuition

September 10, 2012
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Item Response Theory: Developing Your Intuition

Suppose that you accepted my argument from the last two posts on halo effects and bifactor models.  As you might recall, I argued that when respondents complete rating scales, they predominating rely on their generalized impression with a more minor role played by the specific features that the ratings were written to measure.  Consequently, we...

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Structural Equation Modeling: Separating the General from the Specific (Part II)

August 26, 2012
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Structural Equation Modeling: Separating the General from the Specific (Part II)

As promised in Halo Effects and Multicollinearity (my last post), I will show how to run a confirmatory factor analysis in R to test our bifactor model.  In addition, I will include a dependent variable and fit a structural equation mode...

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Halo Effects and Multicollinearity: Separating the General from the Specific

August 20, 2012
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Halo Effects and Multicollinearity: Separating the General from the Specific

In the last post, The Relative Importance of Predictors, I showed how difficult it can be to assess the independent contribution that each predictor makes to the overall R-squared when the predictors are highly correlated.  We spent some time looking at one example where the predictors were ratings from an airline satisfaction study.  As is common in such studies,...

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The Relative Importance of Predictors – Let the Games Begin!

August 9, 2012
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The Relative Importance of Predictors – Let the Games Begin!

What's the one thing we need to do?Marketing researchers are asked this question frequently whenever they analyze customer satisfaction data.  A company wishing to increase sales or limit churn wants to focus only on the most important determinants of those outcomes.   Given the limitations imposed by the available customer survey data, this strategic question is transformed quickly into a methodological one concerning how...

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