Author Archives: Moinak Bhaduri

Whatever your exact interests in data, frequently, inseparable from model-building, stand other related responsibilities. Sample two crucial ones:

a. the checking of how well your model did: the less frequently you make big, bad decisions – like predicting someone’s salary to be $95,000, an estimate far adrift from the real, say, $70,000 in case it’s a regression problem, or saying a customer will buy a product when, in fact, she won’t, under a classification environment – the happier you are. These accuracies are unsurprisingly, often used to guide the model-building process.

b. the explaining of how you arrived at a prediction: this involves unpacking or interpreting the $95,000. The person, due to his experience, makes $10,000 more than the average, due to his education, makes $20,000 more, but due to his state of residence, makes $5000 less than the average, etc. These ups and downs contribute to a net final value.

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It was never meant to last, you know. Statistical measures have their heydays; permanent relevance is no guarantee. The p-value was – and still is – a tool like no other. Through the years it has been caressed and condemned, worshipped and feared, praised and slandered – all the while standing at the crossroads of almost every hypothesis testing, modeling, and prediction. Operationally, a p-value is convenient: we reject, almost mechanically, our null assumption if this value falls below certain discipline-specific thresholds like 0.01, 0.05, etc. Still, its cumbersome construction, triggering its tricky interpretation and stunning misuses, frequently lands it on the wrong side of both practitioners and stats purists. Bodies such as the American Statistical Association routinely issue caution around its use ( Experts have been hearing its death rattle for quite a while. The article “E-values: calibration, combination, and applications” by V. Volk and R. Wang could be the final twist of the knife. Here, the authors offer a promising alternative – the e-value – which can coexist with – and, at times, replace – its troubled ancestor.

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