Predictive analytics often serves as an introduction to data science, but it may not be the best exemplar given its long history and origins in statistics. David Blei, on the other hand, struggles to define data science through his work on topic modeli... [Read more...]

R uses the generic scale( ) function to center and standardize variables in the columns of data matrices. The argument center=TRUE subtracts the column mean from each score in that column, and the argument scale=TRUE divides by the column standard devi... [Read more...]

The website for The Burning House begins with a simple question:If your house was burning, what would you take with you? It's a conflict between what's practical, valuable and sentimental. What you would take reflects your interests, background and pri... [Read more...]

Very early in the study of statistics and R, we learn that random variables can be either categorical or continuous. Regrettably, we are forced to relearn this distinction over and over again as we debug error messages produced by our code (e.g., ... [Read more...]

What is a brand? Metaphorically, the brand is the white sphere in the middle of this figure, that is, the ball surrounded by the radiating black cones. Of course, no ball has been drawn, just the conic thorns positioned so that we construct the sphere ... [Read more...]

The choice modeler looks over the adjacent display of cheeses and sees the joint marginal effects of the dimensions spanning the feature space: milk source, type, origin, moisture content, added mold or bacteria, aging, salting, packaging, price, and m... [Read more...]

Why does lifting out a slice make the pizza appear more appealing?We can begin our discussion with the ultimate feature bundle - pizza toppings. Technically, a menu would only need to list all the toppings and allow the customers to build their own piz... [Read more...]

Religion is a categorical variable with followers differentiated by their degree of devotion. Liberals and conservatives check their respective boxes when surveyed, although moderates from each group sometimes seem more alike than their more extreme co... [Read more...]

Features form the basis for much of our preference modeling. When asked to explain one's preferences, features are typically accepted as appropriate reasons: this job paid more, that candidate supports tax reform, or it was closer to home. We believe t... [Read more...]

Evidently, preference is contextual, or so The Hershey's Company claims in their advertising. I agree and will not repeat the argument made in a previous post on incorporating preference construction into the choice modeling process.Within the framewor... [Read more...]

If the thought of a nice Chianti with that breakfast croissant is not that appealing, then I have made by point: occasion shapes consumption. Our tastes have been fashioned by culture and shared practice. Yet, we often ignore the context and run our an... [Read more...]

The typical introduction to item response theory (IRT) positions the technique as a form of curve fitting. We believe that a latent continuous variable is responsible for the observed dichotomous or polytomous responses to a set of items (e.g., multipl... [Read more...]

Adding a context can change one's frame of reference:Are you courteous? Are you courteous at work? Decontextualized questions tend to activate a self-presentation strategy and retrieve memories of past positioning of oneself (impression manag... [Read more...]

Carl Jung was at least partially correct. We do tend to think in terms of the extremes as shown in this archetypal wheel with rulers versus outlaws and heroes versus caregivers at different ends of bipolar dimensions. Happily, we are not required to ac... [Read more...]

Substantive expertise makes it into the Data Science Venn Diagram from DataCamp's infographic on how to become a data scientist. It's one of the three circles of equal size along with programming and statistics. Regrettably, substantive expertise ... [Read more...]

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Net Promoter believes that customers come in one of three forms: promoters (happy yellows), passives (neutral grays), or detractors (angry reds). Cluster identification is relatively easy for all you need to do is ask the "ultimate question" concerning... [Read more...]

R enables us to "test drive" statistical models by running simulations and analyzing actual data. We can look at the output and get some sense of how the whole thing works. The goal is to provide a realistic application that is not too difficult to fol... [Read more...]

Overview. When responding to questions about brand perceptions or product feature satisfaction, consumers construct a rating  by relying on their overall satisfaction with the brand or product plus some general category knowledge of how diffi... [Read more...]

In 1993, when music was sold in retail stores, it may have been informative to ask about preference across a handful of music genre. Today, now that the consumer has seized control and the music industry has responded, the market has exploded into more... [Read more...]