For the longest time I was puzzled by what it means to “over-fit” a model to one’s data. How can a model describe one’s data too perfectly? Aren’t we trying to get as close to a perfect fit as possible? This one-minute video will show you an example of over-fitting. After watching it, the odd…
Before the days of DATA MINING this was called DATA DREDGING. And for good reasons, because it was considered not a good thing. Almost any dataset will have nonsense correlations, and if you’ve turned on your magical statistical testing tool at the 95% confidence level, five out of every one hundred nonsense correlations will likely…
Every two years marketing executives from more than 60 corporate members of the Marketing Science Institute (MSI) vote on the most important marketing topics they need to understand better. They represent companies like Kraft, Colgate-Palmolive, Bank of America, Nielsen, and Walmart. MSI—a think tank, of sorts, whose mission is to “bridge the academic and business…
Leading practitioners of survey research now agree that online polling and other forms of non-probability sampling can work. The key is to give careful attention to the survey protocols, data collection, cleaning, and back-end weighting so that ultimately the sample being analyzed matches the population you want to know about in as many relevant ways…
Don’t waste money delighting your customers. That’s the message from an intriguing new study and report just issued by the Corporate Executive Board. Why not delight your customers? Because meeting expectations is enough to keep them loyal. Going beyond those expectations and “delighting” them has no measurable impact on loyalty. Quoting from the report: Most…