Net Promoter Score (NPS) Does Not Predict Growth
- it’s a fake science
“Managers have adopted the Net
Promoter Score on the basis that solid science
underpins the technique and that it is superior
to other metrics.
We find no support that for the claim that Net
Promoter is the “single most reliable
indicator of a company’s ability to
grow.”
The above quote is from a Journal of Marketing
article and winner of the
Marketing Science Institute
/H.Paul Root Award “A Longitudinal
Examination of Net Promoter and Firm Revenue
Growth”, Journal of Marketing (2007),
Vol.71, by Tim Keiningham et al.
The Net Promoter Score was developed by Frederick
Reichheld a consultant now well known for making
headline grabbing conclusions based on sloppy
research and thinking.
I previously
pointed out what was wrong with
his claim that small reductions in customer
defection cause massive profit increases.
Then in 2004 he is said to have had an epiphany
describing his prevous work on loyalty as
“powerful but useless”. Keeping
customers didn’t matter so much, having
customers who would recommend you was everything.
So the latest myth he peddles is that asking
customers their likelihood of recommending the
company predicts company growth. He claims it
does so much better than traditional metrics such
as customer satisfaction.
Actually, if you read Reichheld’s Harvard
Business Review article carefully you can see he
employs the same sort of sleight of hand he did
in his customer defection work. Pay careful
attention to the dates, Reichheld in 2003 writes
that starting in the first quarter of 2001
consultancy firm Satmetrix began collecting
customer likelihood-to-recommend responses via
email survey. Each quarter collected 10-15,000
responses gradually building a small dataset
covering 400 companies in a dozen industries.
Reichheld then calculated a Net Promoter score
for each company and compared this to the
company’s growth rate over 3 years (1999 to
2002). Yes, that’s the previous 3 years.
Yes, so the correlation he reports says that
firms that score higher now have previously been
growing.
Reicheld admits on his website that the
statistical analysis in his book was sloppy but
says that since then the consultany company he
worked for (Bain & co) has done more
extensive analysis showing no correlations
between satisfaction scores and company growth,
but excellent correlation for the NPS. However,
Keiningham et al’s Journal of Marketing
article perfectly repeated Reicheld’s
analysis and they found the same or better
correlation between satisfacation and growth
(hence the quote above).
Such correlations say little about causality
(especially when they are backwards in time), as
Reichheld tries to use in his defence, but then
why on earth did he select these cases to
‘prove’ his case ? He even admitted
he’d selected amongst the very best
examples!
In sum, this is
snake oil, fake science.
It’s scary how many CEOs fell for
this.
