Almost once every year someone asks if R has a package for running the MaxDiff procedure sold by Sawtooth.  One such inquiry recently received a reply with a link showing in some detail the R code needed to generate a balanced incomplete... [Read more...]

Survey research deals with the problem of question wording by always asking the same question.  Thus, the Gallup Daily Tracking is filled with examples of moving averages for the exact same question asked precisely the same way every day. &nb... [Read more...]

Context awareness seems to be everywhere, and everyone seems to be saying that context matters.  Gartner foresees "a game-changing opportunity" in what it calls context-aware computing.  The title of their report states it best, "Context Shap... [Read more...]

Are halo effects real or illusory?  Much has been written arguing that rating scales contain extensive amounts of measurement bias.  Some tells us to avoid ratings altogether (What do customers really want?).  Others warn against the use of ratings scales without major adjustments (e.g., overcoming scale usage heterogeneity with ... [Read more...]

A Beginner's Guide to Irrational Behavior started yesterday.  One might not immediately think that such a course would be relevant for statistical modeling.  Well, it is if your statistical modeling uses people as informants.  If the dat... [Read more...]

I raise this question because we see calls for running segmentation with individual estimates from hierarchical Bayes choice models without any mention of the possible complications that might accompany such an approach.  Actually, all the calls seem to be from those using MaxDiff to analyze the data from incomplete block ... [Read more...]

It can be difficult to work your way through hierarchical Bayes choice modeling.  There is just too much new to learn.  If nothing else, one gets lost in all ways that choice data can be collected and analyzed.  Then there is all this ou... [Read more...]

I can see from those of you who have contacted me that there is still some confusion about the claims made by Sawtooth that MaxDiff estimates can be converted to ratio-scale probabilities.  Many of you seem to believe that if attribute A... [Read more...]

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 ... [Read more...]

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... [Read more...]

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... [Read more...]

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... [Read more...]

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... [Read more...]

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... [Read more...]

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 ... [Read more...]

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... [Read more...]

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 ... [Read more...]

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 ... [Read more...]

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... [Read more...]

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... [Read more...]