Human Debt: Why the most dangerous technical debt is not in your code

Marc Hornbeek has spent decades working across engineering, DevOps, security, and reliability disciplines, advising organizations on how to build resilient and high-performing digital systems. In this article, he examines a less visible form of technical debt that can be even more damaging than architectural flaws or outdated tooling. Drawing on insights from his work and his books, Engineering Respect and Trust and Intelligent Continuous Security, he highlights how organizational culture, communication, and trust directly influence system reliability, security, and engineering performance.

Most people assume technical debt lives in code. In reality, the most dangerous form of technical debt often exists somewhere else: in the conversations teams are afraid to have.

Over many years in engineering organizations, I’ve seen systems survive a variety of technical shortcomings, including poor code quality, outdated tools, and imperfect architectures. These issues are visible and measurable, allowing engineering teams to prioritize and fix them.

What is far more difficult to correct is a deeper form of organizational debt caused by issues within relationships and communications, such as:
- Unspoken concerns
- Unresolved conflicts
- Hidden assumptions
- Silent disagreement
- Leadership environments where difficult truths are not easily surfaced

I call this Human Debt.

Human Debt compounds more quickly than any backlog of bugs: it weakens collaboration, erodes trust between teams, and leads to missing important signals. The consequences may include fragile systems, failed releases, a weakened security posture, and teams that gradually lose confidence in one another.

Fixing code is usually straightforward. Fixing silence is far more difficult.

How Human Debt accumulates in engineering organizations

Rather than the way technical debt accumulates within systems, Human Debt develops within relationships, for example, when:
- Engineers hesitate to raise concerns
- Security teams are excluded from architectural discussions
- Operations teams are blamed instead of being consulted
- Leadership rewards compliance over candour

In our book, Engineering Respect and Trust, I, together with my co-authors and fellow DevOps ambassadors, Debashish Bhattacharyya, and Victorio Mosso Zempoalteca explore how respect and trust are sometimes described as “soft” cultural concepts. However, in high-performing engineering organizations, respect allows people to speak, while trust allows people to be heard. Without respect, individuals remain silent. Without trust, warnings are dismissed. And when both conditions are lacking, organizations accumulate Human Debt faster than they can resolve it.

Why Human Debt becomes a security risk

The consequences of Human Debt become even more significant in modern software delivery environments.

Today’s systems are complex, distributed, and continuously evolving. DevOps practices, cloud platforms, AI-enabled systems, and automated pipelines allow software to move into production faster than ever before. While advantageous, this also amplifies the impact of Human Debt.

In Intelligent Continuous Security, I suggest that security failures rarely stem from simple issues like missing patches or misconfigured firewalls. More often, they begin with signals that were overlooked or ignored, such as:
- A vulnerability that someone noticed but assumed was not their responsibility
- A design concern raised privately but not voiced during a meeting
- A risk identified during review but deprioritized due to delivery pressure

Here, Human Debt accumulates and, eventually, that debt falls due. When it does, the consequences can be outages, breaches, compliance failures, or a loss of customer trust.

Trust as the human control plane

Within organizations, trust functions as a “human control plane”. It determines how effectively information moves through the organization and whether critical insights are identified early enough to act upon. In practical terms, trust influences several key aspects, including:

- Whether engineers share early warnings
- Whether teams collaborate across boundaries
- Whether concerns are raised before risks escalate

Without trust, information stops moving, and organizations effectively become blind to emerging issues. This makes it extremely challenging to operate reliable platforms, build resilient systems, and defend against modern cyber threats.

DevOps was never only about automation

DevOps transformed software delivery by breaking down the barriers between development and operations teams. However, DevOps was never only about automation. Its deeper impact lies in the cultural model it promotes, which emphasizes shared responsibility, transparency, and psychological safety among development, operations, and security teams.

High-performing DevOps organizations consistently demonstrate several behaviours:
- They invite dissenting viewpoints
- They reward candour
- They treat questions as contributions, rather than annoyances
- They raise problems early, instead of concealing them

In doing so, they actively prevent the accumulation of Human Debt.

When trust allows people to speak openly, the effects ripple throughout the organization: Engineering quality improves, security strengthens, systems become more resilient, and innovation accelerates. So, the transformation brought about by DevOps is not purely technological; it is fundamentally cultural.

Practical steps to reduce Human Debt

Addressing Human Debt requires intentional leadership and continued professional development. Organizations that successfully implement DevOps, SRE, and modern security practices typically invest in both technical capability and cultural maturity.

Three practical steps can help organizations begin this process.

1. Build a shared language across engineering disciplines

Modern engineering organizations operate as interconnected systems that encompass DevOps, SRE, security, and platform engineering. These disciplines must coordinate closely rather than functioning as isolated specialities.

Professional education can help establish a shared vocabulary and set of practices. DEVOPS INSTITUTE certifications, such as the following, can be beneficial:
- DevOps Foundation
- DevOps Leader
- SRE Foundation
- DevSecOps Foundation
- AIOps Foundation
- Observability Foundation
- Value Stream Management Foundation

These certifications equip teams with common principles and frameworks. When teams understand the same concepts and terminology, communication improves, leading to a reduction in Human Debt.

2. Develop leaders who actively engineer trust

Engineering leadership plays a critical role in shaping a culture of communication. Leaders must intentionally foster environments where concerns are raised early and transparency is rewarded.

Effective leaders encourage dissent and view discussions about risk as valuable contributions rather than criticism. Training programmes such as DevOps Leader® help leaders build these capabilities, encourage trust, and cultivate collaborative, high-performing engineering cultures.

3. Integrate security into continuous delivery

Security can no longer function as a downstream checkpoint at the end of the development lifecycle. Instead, it must operate as a continuous capability embedded throughout the delivery pipeline. DevSecOps training and certifications support this integrated approach by aligning development, operations, and security teams around shared goals. When security becomes collaborative rather than adversarial, organizations reduce Human Debt while strengthening resilience.

The real transformation

Engineering organizations often prioritize improvements in tools, platforms, and automation. While these investments are valuable and often necessary, the most meaningful improvements can sometimes begin with something much simpler: creating an environment where individuals feel safe to raise concerns early on.

Sometimes transformation can begin with a simple moment in a meeting when someone feels safe enough to say: “There’s something we need to talk about.”

When teams trust each other enough to speak honestly, technical debt becomes manageable. Human Debt does not accumulate. And organizations become better equipped to deliver secure, reliable, and innovative systems at scale.

Start reducing Human Debt today.
Explore how DEVOPS INSTITUTE certifications can help your teams build shared language, strengthen trust, and embed security and resilience into modern digital delivery.