They have so many possible biases that are hard to control for.

They can be biased toward positive experiences too, if customers feel the job of the person that helped them is on the line.

What’s better for a manager/executive wanting insight into “how happy are my customers” other than their accounting numbers?

	▲	drdexebtjl 2 days ago \| parent [-]
		Their accounting numbers, sure. NPS is asking your customers "how likely are you recommend us to a friend or colleague?". That's definitely not an accounting number. If you care about this, you can instead ask your _new_ customers if someone recommended you. Or you could hire a third party to do an independent survey among your target demographic.