Net Promoter Score Considered Harmful
&gt; We Can’t Reduce User Experience To A Single Number<p>Growth is a single number, and NPS is measuring growth, not UX.<p>I&#x27;m no big lover of NPS, but this analysis is awful! He claims it&#x27;s bad because he doesn&#x27;t understand it. That&#x27;s not very scientific either.<p>I&#x27;m not sure NPS works well at all, but the idea behind it is obvious. It&#x27;s a growth metric. The goal of NPS is to tell you how many new customers an existing customer will refer to you over the lifetime of their account.<p>This is just like population statistics. NPS is trying to measure your customer birth rate by asking how many customers are (or intend to be) pregnant. It&#x27;s not an accident that there are only two thresholds, and it&#x27;s wrong to conclude that these thresholds indicate a problem with the method.<p>If a customer recommends less than one new customer during the entire time they&#x27;re with you, then you have a replacement rate less than 1, and you&#x27;re losing customers over time. If you have a replacement rate between 1 and 2, and your customer lifetime is long (say, years) then you aren&#x27;t growing fast. If your replacement rate is 2 or higher, and your customer lifetime is short (say, weeks) then you are growing more than 200% month over month virally, without the need for marketing.<p>What the people who designed NPS did, I am sure (meaning I&#x27;m speculating, but giving the strongest possible interpretation), is measure some responses and compare it to the number of actual referrals, then drew the lines where the referral rates cross from negative growth to neutral grow, and from neutral growth to positive growth. That&#x27;s what I would do. And it seems plausible that people who give a score of 6 or less won&#x27;t end up referring anyone, on average.<p>Sadly, the article doesn&#x27;t conclude with any real alternatives for measuring growth. Since NPS is an indirect growth metric, the better answer may be to simply measure your growth directly. That means understanding engagement and activity, not just counting how many accounts exist, but other than that, counting your active customers is a single number that will reliably tell you growth, and can&#x27;t be gamed by your customers -- it can only be gamed by yourself and your team.