Walmart: Where is a statistician when you need one?
Extracted from the shareholder letter of the last Walmart annual report:
Improving Customer Experience
We continue to invest in improving the customer experience in our stores - faster checkouts, friendlier service and cleaner premises. Our customers are taking note. We survey almost two million customers every quarter, and they
are validating the improvements.
I couldn't fathom this. Surveying nearly 8 million people per year means that Walmart has a better handle on what the population wants that just about anyone.
But somewhere I learnt the central limit theorem and the law of large numbers suggests that you don't obviously need to survey that many people unless you are dealing with very fine nuances...
So please dear readers - what is Walmart doing here? And why does it give them a competitive advantage?
John Hempton
PS. If Walmart were a political party surveying that many people I would think were push polling. It is not that - so what is it?