The Zone of Tolerance Model of Customer Satisfaction is a refinement of the gap model described here and has been around since the 1990’s.

We can define the relationship between customer satisfaction and other variables this way:

The Tolerance GAP is the difference between desired service and the level of service considered adequate. The larger that gap, the more likely the customer will be dissatisfied.

The chief strength of this is that it explains something the expectation models do not — why customers return to companies where the service is bad.

How so? The model suggests that there is a wide zone of customer service quality that is…well, OK. Barely adequate. So long as the company stays within that zone, the customer will not have a highly emotional reaction, and so will remain a customer.

So, the implication of the model is that you have to be quite bad to actually lose a customer forever, but the flip side is that it’s also hard to WOW a customer too.

That seems to correspond well to how real people actually behave when they encounter poor service, particularly the fact that they often return, particularly if the establishment has other desired characteristics — lower price, more convenient, closer location, etc.

However….

It’s important to remember that customer behavior, wants, needs, expectations are very fluid — they depend on an immediate context, and this applies here. It would be a mistake to think that customers have some consistent rule — let’s say they’ll only wait 5 minutes, that they apply to every single interaction.

Even at the same establishment, the rules or norms a customer applies will change depending on his or her situation. So a mother late picking up her child from school is clearly going to apply a different “rule” about how long she will wait in line compared to someone out for leisurely shopping.

That’s something we need to understand when looking at any customer satisfaction model.