On the Apdex Exchange blog, I’m writing a series of posts about Generalizing The Apdex Standard. The ideas I developed (together with any public input) will evolve into a new draft of the Apdex specification. The latest post is on Apdex as a (Key) Performance Indicator. Here's a brief introduction:
Metrics, Performance Indicators, and KPIs
If you spend more than a few minutes learning about Key Performance Indicators, you will surely read words like these: All KPIs are metrics, but not all metrics are KPIs. Furthermore, for the adjective Key in "KPI" to have any real meaning, it must also be true that not all performance indicators are KPIs. Jonathan Becher writes:
While metrics can be a measure of just about anything, KPIs are the measures that matter most
So we have defined a three level hierarchy: metrics, performance indicators, and KPIs.
An Apdex index is certainly a metric, and--based on the Apdex definition alone--it is also a performance indicator, because an Apdex score indicates the degree to which individual measurements of actual performance meet previously defined targets. This applies regardless of the data being summarized in the Apdex score. But can an Apdex index also be used as a Key Performance Indicator, or KPI? The answer depends on how you define "KPI", a term with no single universally accepted meaning.
Many authors have proposed definitions, so I evaluate Apdex against a list of proposed KPI characteristics found in the articles and papers I listed in my metrics bibliography. For the details, read my post on the Apdex Exchange blog.
Contribute Your Input
The first three posts in the series are:
If you’ve ever used Apdex, or thought about how it could be used, consider contributing your own thoughts in the comments on the Apdex Exchange blog. I will definitely reply, and also take your input into account as I draft a new generalized Apdex specification. The result will be much more authoritative if it reflects the consensus view of people who want to apply the Apdex method for reporting in their own organizations.