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Putting Apdex in Context

The Apdex method can play a useful role in any SLM process. But it is not the whole solution. Apdex is certainly a very useful tool when you have collected measurements and need a simple way to show how well those measurements reflect your goals. But first you have to decide what those goals should be.

This aspect of SLM is a broad subject that I’ve explored previously, for example:

The SERVQUAL Gaps Model

Today I was looking for a more systematic way to put Apdex in context, to focus on where Apdex can — and cannot — help. In the process, I discovered the SERVQUAL “gap” model, first defined in a 1985 paper, A Conceptual Model of Service Quality, by Parasuraman, Zeithaml, and Berry. There’s a link to a book and a (2.3Mb) copy of the original paper below. For a more concise and readable introduction online, I recommend the Theory Of The Gaps Model In Service Marketing, published by the Marketing Association of Australia and New Zealand.

In this model, the so-called “gaps” identify places where quality is measured or perceived differently by different participants in the delivery of a service to customers. The original version of the model described five gaps. A later refinement added two more, as illustrated in the figure below, published last year in Steve Lesem’s interesting blog, Cloud Storage Strategy:

SERVQUAL Gaps Diagram

In his post,  Service Provider Strategies for Building Trust, Steve also provides these concise descriptions of the seven gaps:

Gap 1: Customers’ expectations versus management perceptions: caused by the lack of a marketing research orientation, inadequate upward communication and too many layers of management.

Gap 2: Management perceptions versus service specifications: caused by an inadequate commitment to service quality, a perception of unfeasibility, inadequate task standardization and an absence of goal setting.

Gap 3:
Service specifications versus service delivery: caused by role ambiguity and conflict, poor employee-job fit and poor technology-job fit, inappropriate supervisory control systems, lack of perceived control and lack of teamwork.

Gap 4: Service delivery versus external communication: caused by inadequate horizontal communications and propensity to over-promise.

Gap 5: The discrepancy between customer expectations and their perceptions of the service delivered: caused by the influences exerted from the customer side and the shortfalls (gaps) on the part of the service provider. In this case, customer expectations are influenced by the extent of personal needs, word of mouth recommendation and past service experiences.

Gap 6: The discrepancy between customer expectations and employees’ perceptions: caused by the differences in the understanding of customer expectations by front-line service providers.

Gap 7: The discrepancy between employee’s perceptions and management perceptions: caused by the differences in the understanding of customer expectations between managers and service providers.

The magnitude and the direction of each gap affects service quality; the ultimate goal when managing service quality should be to eliminate all the gaps — to get everyone on the same page. Common sense, really — but achieving that goal is no simple matter. I’m planning to write at least one future post about Closing The Gaps.

The Apdex Connection

While the Apdex method has many conceivable applications, I believe that most uses of Apdex today involve comparing:

  • Measurements of a delivered service, collected by the organization delivering the service
  • Targets set by the business management or technical staff of that organization

It would interesting to hear of other applications. But if my assumption is correct, mapping that information onto the SERVQUAL framework, we see that most uses of Apdex for SLM address at most two of the potential gaps that can undermine service quality: Gap 2, and Gap 3. If technical staff set the targets, Apdex is being used to focus on Gap 3 alone. If the targets are set by business management, then Apdex is being used to focus on the sum, [Gap 2 + Gap 3].

What can you do about the other five gaps that Apdex does not address? That’s a big topic, too big to tackle systematically here. However, one thing the SERVQUAL model highlights is the vital significance of Gap 5, the difference between expected service and perceived service. Note that Gap 5 is also a component of both Gap 1 and Gap 6, so it affects all three of the gaps that customers actually care about.

Customers’ expectations are influenced by their needs, their prior experiences, and what they have read or heard. To eliminate Gap 5, you have to understand those factors, and set the targets for delivering your service accordingly. If you don’t do that, you can have wonderful Apdex scores, eliminating Gap 2 and Gap 3, while delivering very poor levels of service. In Apdex terminology, an Apdex score is only as good as your T value. To use Apdex to manage any measured service effectively, your T value for that service must be designed to eliminate [Gap 2 + Gap 3 + Gap 5].

SERVQUAL References

  1. A Conceptual Model of Service Quality and Its Implications for Future Research, A. Parasuraman, V.A. Zeithaml, and L.L. Berry. Journal of Marketing, Vol. 49, Fall 1985 [2.3Mb pdf at Web Performance Matters]
  2. Delivering Quality Service, V.A. Zeithaml, A. Parasuraman, and L.L. Berry. The Free Press, 1990 [2009 Paperback edition at Amazon]

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