Apdex: A Standard for Reporting Application Performance

Imagine a simple numerical measure of user satisfaction with the performance of enterprise applications. It exists and it's catching on. It's called an Apdex score. Here's why it is and what it is.

Why Apdex? For two decades CIO magazine has polled IT industry leaders to understand their burning issues, and every year a top goal has been to align IT and business performance. In this year's survey 82 percent of respondents said aligning IT and business was their number one activity. Think about it. CIO's have not solved their number one problem for the past 20 years!

For those 20 years CIOs have applied management technology as a nostrum to align application delivery technology to the business. Now more than 50 performance measurement tool vendors vie with each other on the accuracy and detail of their data. Enterprises often use more than one of these vendors and add home-grown tools to the mix. The result is a sea of numbers which fail to shed light on the user's actual experience.

To solve this dilemma, NetForecast organized a cadre of vendors to develop and specify a new way to report on performance using measurement capabilities that already exist. The result is the Application Performance Index or Apdex. Apdex is an open standard so you can use it freely.

What is Apdex? Apdex is a numerical measure of user satisfaction with application performance that provides a uniform way to report on the user experience. It converts many measurements into one number on a zero to one scale (0 = no users satisfied, 1 = all users satisfied). It can be applied to any source of end-user performance measurements. If you have a measurement tool that gathers timing data like a user could gather with a stopwatch, then you can use it.

Apdex translates many individual response times measured at the user task level, into a single number. A task is an individual interaction with the system within a larger process. Task response time is the elapsed time from when a user does something (mouse click, hits enter or return, etc) to when the system (client, network, server) responds so the user can proceed with the process. This is the time during which the human waits for the system. These individual waiting periods define the "responsiveness" of the application to the user.

Apdex is governed by the Apdex Alliance, a non-profit organization governed by its members. The Alliance promotes the Apdex standard and associated methodology, and also runs an education and community outreach program. The Alliance is supported by about a dozen companies and more than 800 individual supporting members.

In upcoming postings we will explain the Apdex standard and supporting methodologies. We will describe how to report application performance so business managers understand, and we will help you reach that holy grail of business/IT alignment that has eluded CIOs for the past 20 years.

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Copyright © 2008 IDG Communications, Inc.

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