We all try to do our best. But humans tend to be overly optimistic about what they can actually accomplish. You say you’ll go to bed early, but you find yourself still up watching Kitchen Nightmares at 12:35am. You say you’ll respond to customers within 24 hours, but instead it’s 31 hours. It’s not your fault – you got stuck in a meeting, had to run an errand, or had some very time-intensive other emails to answer first.

That’s a problem, though. According to a new study, failing to respond to a customer within the time period you promised will hurt their satisfaction far more than simply making a less ambitious promise!

The smart folks over at the Corporate Executive Board did a study wherein they tested three groups: two that delivered on their 24- and 48-hour respective promises, and one that failed to respond within their promised time. The results are below (CSAT is fancy-business-speak for Customer Satisfaction).

customer expectations experiment

Changing their promise from a 24-hour response time to 48-hours only decreased customer satisfaction by 13% – as long as they responded in time. Failing to respond in the advertised time period decreased satisfaction by almost 50%!

You can also see that overpromising results in the customer spending more effort to get help…as they may have to email you again asking you to answer their original query, or go elsewhere for an answer.

Warning: DO NOT take this as an excuse to be lazy about response times. We’ve already proved that faster responses make customers happier. Strive for your fastest – advertise your most consistent.

Zappos is, of course, the prime (if perhaps overplayed) example of this. They never promise free overnight shipping, but they end up giving it to many people. At this point they probably could promise overnight shipping and it would be true 90% of the time. But by making it an unexpected surprise, the 90% of customers who get this surprise upgrade become ecstatic evangelists…rather than having 10% of customers be let down and grumpy.

This is probably the easiest advice you’ll ever get from this blog. Go look at how fast you respond to customers. Change your promised response period to match the response time you consistently hit (here’s how to change your autoresponse in UserVoice, if you’re a customer). Boom. You just made your customers happier.

(Now go work on improving your response time!)