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Apdex Specification Templates

I’m writing a series of posts about Generalizing Apdex. This is #9.

Previously I analyzed the current Apdex specification, asking the question Which Apdex Features Can Be Generalized? and answering with a list of topics to be worked on. I began by establishing working assumptions about document structure and terminology:

Separate Core Apdex Rules from Domain-Specific Rules
We should separate the core Apdex method into its own specification, and create distinct spec documents that contain any rules associated with domain-specific applications of the Apdex method. I will refer to the domain-specific components of the spec as addenda.

Apdex Document Names
I will refer to the new core specification as Apdex-G. This document will contain definitions and notation for all the core Apdex features we decide to generalize, such as targets, zones, and scoring. If I need to refer to a domain-specific addendum, I will use a suffix appropriate to their particular domain, such as Apdex-R for response time, Apdex-V for VOIP quality, Apdex-S for service quality, Apdex-N for network performance, etc.

As I have begun work on the details (see Generalizing the Apdex Language and Separately Configurable Thresholds in Apdex-G), a mental framework for the structure and content of each document has begun to emerge. This post aims to solidify that framework by laying out draft templates for Apdex-G and the addenda.

The table below contains my current thinking about the division of content between the Apdex-G “Master” spec and an addendum. Using the structure of the present spec as a starting point, it lists the number and title of each section, and describes briefly the content I envision for Apdex-G and the addenda in each section.

Section Number [1] Section Title [2] Type [3] Content of Apdex-G Content of Domain-Specific Addenda [4]
1 Introduction M+d Brief generic description of Apdex [Apdex-G] + brief introduction to the addendum domain
1.1 Apdex Specification Documents M+d Description of role of Apdex-G and addenda [Apdex-G] + relationship of this addendum to Apdex-G
1.2 Document Status M/D Ratification history and status of Apdex-G Ratification history and status of this addendum
1.3 Broader Apdex Goals M/- Brief overview of Alliance goals [Apdex-G]
2 Index Overview M+d Reasons to reduce measurements to an index [Apdex-G] + domain-specific benefits
2.1 Index Objectives M+d Core Apdex qualities [Apdex-G] + domain-specific qualities
2.2 Terminology M+d Particular terms used in Apdex-G [Apdex-G] + particular terms used in this addendum
2.3 Measurement Types M/D How Apdex-G is not domain-specific; point to addenda Domain-specific applications of Apdex (as in current spec [5])
2.4 Measurement Subtypes -/D Empty; point to addenda Domain-specific refinements (e.g. various components of response-time in Apdex-R [5])
2.5 Satisfaction Levels M+d Generic concepts of satisfaction levels, performance intervals, thresholds, zones [Apdex-G] + domain-specific applications of satisfaction levels, etc.
2.6 How the Index Works M/- Overview of the properties of the Apdex index [Apdex-G]
3 Apdex Calculation Inputs M+d Brief introduction (as in current spec) [Apdex-G] + domain-specific comments, if needed
3.1 Measurements M+d General guidelines about measurement data [Apdex-G] + domain-specific guidelines about measurement data
3.2 Report Groups M+d General guidelines about report groups [Apdex-G] + domain-specific guidelines about report groups
3.3 Reprt Group Size M+d General guidelines about sample counts [Apdex-G] + domain-specific guidelines about sample counts
3.4 Thresholds M+d General guidelines about thresholds [Apdex-G] + domain-specific guidelines about thresholds
4 Calculating Apdex M+d Brief introduction (as in current spec) [Apdex-G] + domain-specific comments, if needed
4.1 Apdex Formula M+d Full specification of the Apdex computation [Apdex-G] + domain-specific constraints, if applicable
4.1.1 The Standard Formula in Action M+d Comments on standard formula [Apdex-G] + domain-specific constraints, if applicable
4.1.2 Alternative Scoring in the Tolerating Zone M/D Option to implement alternative scoring in an addendum Domain-specific scoring, if applicable
4.2 Dealing With Exceptions M+d Universal rules for handling measurement exceptions [Apdex-G] + domain-specific rules about measurement exceptions
5 Reporting the Index M+d Brief introduction (as in current spec) [Apdex-G] + domain-specific comments, if needed
5.1 Reporting the Apdex Value M+d Universal rules for displaying Apdex values [Apdex-G] + domain-specific rules (if any) about displaying Apdex values [6]
5.1.1 General Cases M/- Guidelines for describing Apdex values in the general case [Apdex-G]
5.2 Uniform Output File M+d Format of the Uniform Output File [Apdex-G] + domain-specific examples (if any) of Uniform Output
5.3 Indicating Sample Size M+d Universal rules about displaying the Apdex sample size [Apdex-G] + domain-specific rules (if any) about displaying the Apdex sample size [6]
5.4 Apdex Quality Ratings M/- Universal guidelines about computing and displaying Apdex quality ratings or grades [Apdex-G]
6 References M+d Common references about the Apdex methodology [Apdex-G] + domain-specific references
7 Glossary M/- Common Apdex Glossary [Apdex-G]
Table 1. Structure of Apdex-G and Addenda

Explanatory Notes:

  1. I have assumed that all Apdex specification documents will have an identical structure, with only the content differing among documents, even if some sections are empty in some documents. I believe this approach will simplify document construction and usage.
  2. I have shortened and generalized many of the present spec’s section titles.
  3. When allocating content, there are just four distinct possibilities; the ‘Type’ column indicates which pattern applies in each section:
    • (M+d): A master spec and a domain-specific variant
    • (M/-): A master spec only
    • (-/D): A domain-specific spec only
    • (M/D): Independent content in each document.
  4. In the column describing addenda, the notation ‘[Apdex-G]’ means ‘Refer to this section of Apdex-G, or duplicate the corresponding Apdex-G content in the addendum, for readability’. At this stage we do not need to decide which approach is preferable.
  5. Because the domain-specific content of the current spec will be allocated to Apdex-R, I am using Apdex-R as an example here, and in other posts. This helps to test my model for the content of an addendum, but my intent is to describe a pattern or template that will work for all domain-specific addenda.
  6. Ideally, the common Apdex-G specification for reporting results should apply to all measurement domains, but we should not rule out possible justifications for alternative formats.

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