Complexity Index

A compound measurement of an activity which factors in the number of tasks, total duration and required mental focus and intelligence.

At Slaughter Development, we characterize the overall challenge of an activity by rating it with a complexity index. Our metric consists of a simple four point scale, ranging from low to very high. This rating provides a means for sorting a company’s activities and targeting those best suited to available resources.

The term “complexity index” comes originally from the field of petroleum engineering, where it describes how effectively a refinery is able to produce secondary products in relation to the primary task. Managing a variety of objectives and processes simulatenously is difficult, and having a rigorous measurement system helps to understand the impact of procedures and policies on overall system dynamics.

Index Ratings

Measuring system complexity is itself a complicated task, but a fairly straightforward heuristic can provide a general estimate in the form of this index. Three markers are used to classify activities into one of the four levels.

Number of Subtasks

The number of mentally discrete steps required in a process provides insight into overall complexity. For example, accepting a customer’s payment by check might begin (1) finding the correct record (2) keypress entry of payment information (3) storing check in a lockbox and finally (4) a daily trip to the bank. A more complex task, such as launching a marketing campaign or planning a conference, would have many more steps. These subtasks often number in dozens or hundreds and are expressed on a checklist or planning spreadsheet. The following table outlines a general guideline for this marker:

3-5 steps 6-10 steps 10-25 steps 25+ steps
Subtask Marker S-1 S-2 S-3 S-4

Intellectual Markers

Complexity is not strictly a measure of the number of steps, but also of how difficult those steps are to complete. Methodology engineering is focused on difficulty as a factor of intellectual energy. The grid below offers an outline of four major marker levels.

Intellectual Marker Description
I-1 Straightforward, repetitive tasks which can be completed in a handful of steps, usually ranging from a few minutes to a few hours. Includes most routine work, such as data entry, basic information processing, archiving, follow-up and light service or assembly tasks.
I-2 Activities which require evaluation, judgement, and exception handling. Includes rectifying errors, handling inaccurate or incomplete requests, answering basic service requests and domain-specific questions as well as medium assembly tasks.
I-3 Work which requires troubleshooting, problem-solving, higher-order thinking, creativity, emotional intellegence, composition of oral and written communication and workspace organization.
I-4 Highly inventive work, especially involving synthesis, brainstorming, lateral thinking, design, architecture, strategic planning and scientific, mathematical or logical reasoning.


Generally speaking, simple tasks are done quickly and complex tasks take longer. Length of time is not a sole indicator; for example, a translator might only require a few seconds to restate an idea in another language, and an administrative assistant might need an entire morning to sort mail across a hundred mailboxes. Classifying activities by the length of time comprises a third element of the complexity index:

1-8 hours 4-16 hours 16-32 hours 32+ hours
Duration Marker D-1 D-2 D-3 D-4

Using the Index

Slaughter Development incorporates the complexity index through the full methodology engineering lifecycle, but especially when evaluating your current environment as part of Workplace Diagnostics and creating new designs during Business Process Modeling. Collecting these scores and utilizing the results provides an incredible benefit to our clients.

You can prepare for our visit and help evaluate existing systems using these concepts. When you are ready to learn more, contact us to set up an initial consultation.

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