Imagine a house built over time by different teams, with no architect overseeing the whole thing. Each room functions, but the light switches move around on different floors and the doors don't all open the same way. The inhabitants have eventually adapted to these quirks and no longer pay them any attention. For someone discovering the house, however, every movement becomes a source of hesitation and confusion. The house remains habitable, but if it were ever to be renovated or sold, harmonising the whole thing would become complex and expensive.
This situation is common in digital systems. As they evolve, inconsistencies appear between the user journeys, content, interfaces, or tools. Like a house that has been extended without an overall vision, a digital ecosystem can continue to function while becoming increasingly difficult to understand, maintain, and evolve.
In this article, discover what digital coherence debt is, how it forms, why it ends up being costly for organisations, and some avenues to help you identify it.
What is digital coherence debt?
The digital coherence debt refers to the progressive accumulation of inconsistencies within a digital system. This can concern pathways, content, interfaces, tools, the language used, or even the behaviour expected from the user. Digital coherence debt is formed when additions are made even though they create friction with what already exists.
A new section that uses different vocabulary. A tool that behaves differently from others. A process that contradicts established practices. Each deviation seems minor at the time it appears. Taken together, they make the system increasingly difficult for the user to understand and for the teams to maintain coherently. Taken in isolation, these deviations seem trivial, It is the accumulation that constitutes a digital coherence debt.
For a long time, I observed the same difficulties in digital projects: inconsistent user journeys, contradictory tools, content that was no longer aligned. The concept of technical debt helped me understand part of the problem, but I was missing a term to describe these inconsistencies that went beyond the code. This is how I started using the expression «digital coherence debt». – Sandra Pomart, founder of Pépinia
Technical debt refers to the future costs associated with development choices that prioritised speed over code quality. It accumulates and the later it is dealt with, the more expensive it is to correct. Consistency debt follows the same mechanism, but its scope extends beyond the code. It results from decisions taken to go faster, simplify delivery or reduce an immediate cost, without measuring their impact on the overall understanding of the system. Both forms of debt have one thing in common: the more they accumulate, the more they cost to correct.
The debt of coherence does not only arise over time. It can appear from the very first decisions A poorly chosen tool, a poorly structured path from the outset. The age of the system is not the only factor. The initial choices are just as important.
How do organisations accumulate digital coherence debt?
Most digital devices are not built all at once. They grow by successive additions: a new tool, a new section, an additional channel. Each addition follows its own logic, without any review of what already exists. The result seems to work, but the user feels the variations at each stage of their journey.
Changes in teams or service providers also amplify the phenomenon. When design decisions are not documented, new teams reinterpret previous choices in their own way. Variants appear without anyone having decided on them.
Without a common framework, each department goes its own way. Marketing, IT, communications, business: everyone has their own habits and their own tools. No one has an overview. It's the user who experiences it each time they move from one section to another.
It is the accumulation of these discrepancies that poses the problem. The system becomes more difficult for the user to understand. Each correction becomes more expensive than the last.
The cost of digital coherence debt
The more technical debt accumulates, the longer and more expensive it is to fix. Three main aspects are impacted:
The impact on the user experience
- Navigation headings that change from section to section.
- Buttons that behave differently from one page to the next.
- A level of language that varies for no apparent reason.
- And so on.
Users have to make an extra effort to understand: their confidence decreases and abandonment increases.
Impact on the organisation
Strategic impact is harder to measure but just as real. An inconsistent system blurs the messages sent to users. It undermines the clarity of the organisation. It also forces costly choices: creating gateways between tools that were not chosen together, managing systems that do not communicate. These costs could have been avoided.
Impact on teams
The impact on teams is also often underestimated. Working on an incoherent system means spending time managing exceptions, dealing with repeated arbitrations and finding temporary solutions. This time is not spent moving the system forward: it's spent keeping it afloat.
Why is digital coherence debt often misidentified?
It is common to attribute the problems of a digital device to isolated causes: an insufficient conversion rate, poorly written content, a technical problem. These partial diagnoses lead to one-off corrections that have no effect unless the root cause is identified. Treating a symptom without identifying the source does not reduce the debt - it may even mask it.
A site can be visually coherent and structurally incoherent at the same time. Dealing with appearance without dealing with architecture does not solve the underlying problem. Nor is it linked to a lack of resources: the best-equipped organisations can accumulate a significant coherence debt, precisely because they have the resources to multiply initiatives without coordinating them. Coherence is a question of governance and method before it is a question of budget..
Let's take the example of an international organisation with several subsidiaries. Each entity has its own teams, its own tools and its own digital practices. There's no shortage of resources, but in the absence of a common framework, each subsidiary builds its system according to its own logic and its own systems. The result: user experiences that break down into multiple languages, non-interoperable tools and coordination costs that soar as soon as a project involves several entities.
Another example: a local authority that launches a website redesign, a citizen portal, and a mobile app in parallel – without a common framework and with teams that exchange little or not at all – produces coherence debt even with a substantial budget.
How to identify a digital coherence debt?
Assessing the debt of coherence cannot be done by looking at the digital device section by section. An analytical framework is needed that covers the whole, to reveal the discrepancies between what the device is supposed to produce and what it actually generates. To initiate a coherence debt diagnosis, five points allow for a quick assessment of the situation.
- Structural coherence - Do the pathways follow a stable and predictable logic from one end of the system to the other?
- Semantic consistency - Are the same terms used everywhere: in the interface, content and communications?
- Behavioural consistency - Do similar components behave in the same way, whatever their location in the device?
- Editorial consistency - Does the content produced by different teams fit into a common framework, regardless of when it was produced?
- Consistent governance - Is there a shared body or framework for arbitrating alignment issues between departments?
These five questions do not constitute a coherent debt audit. They make it possible to identify quickly where tensions are greatest and to decide where to concentrate efforts as a priority.
Why is the digital coherence debt increasing today?
Digital coherence debt isn’t a new phenomenon, but several developments are currently contributing to its accelerated accumulation. Organisations are producing more content, using an increasing number of tools, and multiplying touchpoints with their users: websites, mobile apps, social networks, business platforms, client portals, conversational assistants, and online services. Each new device meets a legitimate need but also introduces an additional risk of inconsistency if designed or managed independently of the others.
In parallel, technologies have become more accessible. SaaS solutions, CMS, no-code tools, and, more recently, artificial intelligence allow teams to quickly create content, forms, applications, or digital spaces without systematically relying on technical teams. This autonomy fosters innovation and responsiveness, but it also multiplies local initiatives that do not always fit into a broader vision.
Organisations themselves are evolving. Projects are increasingly cross-functional, suppliers come and go, teams change, and responsibilities are shared across multiple departments. Without common governance, each department optimises its own area based on its objectives. Taken in isolation, these choices are often relevant. However, when taken together, they gradually produce a system that is more difficult to understand, maintain, and develop.
The digital coherence debt is not increasing because organisations are performing worse than before. It is increasing because digital ecosystems have become vaster, more distributed, and evolve more rapidly. The faster the capacity to produce digital increases, the more the capacity to preserve its coherence becomes a strategic issue. It is precisely this gap between the speed of production and the capacity for coordination that is currently fuelling the digital coherence debt.
In most organisations, a digital consistency debt already exists. A page that contradicts another, a form that links to a service that no longer exists, or an online journey that ultimately ends with a phone call are just a few examples.
These situations are not isolated anomalies. They are the result of an accumulation of decisions taken separately, often to move faster, respond to a constraint or launch a new service without questioning the existing system.
With time, these inconsistencies add up. The system becomes harder for users to understand, more complex for teams to evolve, and more costly for the organisation to maintain.
Recognising the existence of a digital coherence debt is a first step. Reducing it then involves progressively realigning the pathways, content, interfaces, tools, and governance methods that structure the digital experience.
This work is not solely about design or technique. It is above all a matter of method, governance and an overall vision. The longer an organisation waits to address its digital coherence debt, the more each new project risks amplifying it. Restoring coherence does not mean going backwards, but rather giving the system the capacity to evolve sustainably.