Aim/Purpose
We establish a conceptually rigorous definition for the widely used but loosely defined term “fitness”. We then tie this definition to complexity, highlighting a number of important implications for the informing science transdiscipline.

Background
As informing science increasingly incorporates concepts of fitness and complexity in its research stream, rigorous discussion and definition of both terms is essential to effective communication.

Methodology
Our analysis consists principally of a synthesis of past work in the informing science field that incorporates concepts from evolutionary biology, economics and management.

Contribution
We provide a rigorous approach to defining fitness and introduce the construct “extrinsic complexity”, as a measure of the amount of information required to predict fitness, to more fully differentiate this form of complexity from other complexity constructs. We draw a number of conclusions regarding how behaviors under low and high extrinsic complexity will differ.

Findings
High extrinsic complexity environments are likely to produce behaviors that include resistance to change, imitation, turbulence and inequality.

Recommendations for Practitioners
As extrinsic complexity grows, effective search for problem solutions will increasingly dominate employing recommended solutions of “best practices”.

Recommendation for Researchers
As extrinsic complexity grows, research tools that rely on decomposing individual effects and hypothesis testing become increasingly unreliable.

Impact on Society
We raise concerns about society’s continuing investment in academic research that discounts the extrinsic complexity of the domains under study.

Future Research
We highlight a need for research to operationalize the concepts of fitness and complexity in practice.