Variance, sampling, and uncertainty
Replace one-run demos with repeated measurements, slices, confidence intervals, rare-failure hunting, and release evidence.
A new book by Jason Arbon
Engineering Confidence in Non-Deterministic Systems
The practical operating manual for people who have to decide whether AI-generated code, agents, models, and products are trustworthy enough to ship.
First edition. Amazon print and Kindle editions are being prepared.
The argument
AI can produce more code, answers, designs, and decisions than any team can review the old way.
Most AI spending today still lives in experiments. The gap between an impressive demo and a production system is not usually another prompt trick. It is confidence: evidence that the system is useful, safe, economical, observable, reversible, and reliable enough for the people who depend on it.
Testing AI starts with testing because that is the doorway software teams recognize. It ends at confidence engineering: the operating discipline for shipping systems that vary from run to run, learn from changing data, call tools, personalize themselves, and behave differently under production load.
The book moves from first principles to operating practice: variance, sampling, statistical evidence, human and LLM judges, eval design, RAG, agents, generated code, security, observability, bias, interpretability, robotics, governance, and the future of AI testing itself.
Inside the book
Not a catalog of tools. Not a stack of prompt recipes. The book connects measurement, engineering, operations, security, and judgment into one practical discipline.
Replace one-run demos with repeated measurements, slices, confidence intervals, rare-failure hunting, and release evidence.
Use p-values, effect sizes, power, paired tests, calibration, abstention, and practical significance without statistical theater.
Design rubrics, calibrate humans and LLM judges, measure disagreement, manage labels, and build evals tied to product risk.
Test retrieval separately from generation, score tool trajectories, verify integration behavior, and catch code that looks right but is wrong.
Threat-model prompt injection, MCP permissions, poisoning, guardrails, dangerous capabilities, deception, and containment boundaries.
Build observability, SLOs, canaries, incident response, cost controls, robotics simulation, governance, and continuous AI-led testing.
Who it is for
AI is collapsing the old walls between building, testing, product judgment, and operating software. The readers differ; the release decision is shared.
Learn how to validate code and systems you did not fully write, including hidden integration, security, data, and operational failures.
Move beyond brittle exact assertions into evals, probabilistic evidence, production traces, risk slices, and human-machine review systems.
Connect prompts, models, data, retrieval, tools, policies, user experience, cost, and release controls into one testable system.
Ask for evidence that supports ship, hold, canary, rollback, investment, governance, and customer-risk decisions.
What changes after reading
You start asking the sharper questions that turn ambiguous behavior into engineering evidence.
Coming soon
Testing AI will be available on Amazon in print and Kindle editions. The purchase link will appear here as soon as the listing is live.