Definitions first.

According to COSO, internal control is a set of processes and actions that help a company meet its goals, whether that means running efficiently, reporting accurately, or staying compliant. These controls are part of daily operations and are used by managers and employees.

Internal audit, on the other hand, is independent. It doesn’t take part in day-to-day processes. Instead, it evaluates how well those processes and controls are working and offers advice on how to improve them. As explained in the IIA’s Three Lines Model, internal audit is the third line of an organisation’s defence, offering objective insight to help leadership make better decisions.

A good way to understand their roles is to think of them like two sides of the same brain:

• Internal control is the left side: focused on structure, discipline, and routine.
• Internal audit is the right side: focused on analysis, reflection, and seeing the big picture.

One can’t work well without the other. And when they collaborate, the organisation can respond to risks faster, adapt to change, and perform better overall.

Internal Control and Internal Audit: Stronger Together

Internal control and internal audit both play critical roles in managing risk. While their focus often overlaps, especially in high-risk areas, their perspectives and methods differ. Internal audit operates independently, assesses the effectiveness of controls, and prioritises broader patterns and systemic issues. When these functions work in isolation, gaps and inefficiencies can appear. Risk may be missed, and effort duplicated. But when they’re connected, the organisation gains both operational detail and strategic oversight.

It’s a bit like having a guardsman who patrols the premises daily and a detective who investigates deeper patterns and hidden threats. If they don’t talk to each other, they might both focus on the same safe corner of the grounds, while the real problem goes unnoticed elsewhere. But when they share information, the guardsman can report early signals, and the detective can connect the dots.
The result? A more complete picture, faster action, fewer surprises.

In one organisation, both the internal control team and internal audit focused on vendor payments, but approached the topic separately. The control team assessed whether procedures were being followed. The audit team came in later to review the same area, but from a different angle: testing the effectiveness of those controls, checking for hidden patterns, and evaluating the broader risk environment.

Without coordination, they missed a fast-growing risk in digital procurement, where inconsistent approval workflows were starting to create exposure.

With better alignment, internal control could have flagged the issue earlier, and the audit could have validated it independently, helping the organisation respond faster and more confidently.

Working together means:

• Fewer blind spots
  Internal control teams are closest to operations and often the first to notice potential issues. Internal audit, with its independent view, can validate those observations and spot patterns that may go unnoticed at the process level.
• Less duplication
  When audit and control functions share their plans, testing efforts can be better aligned. This reduces the burden on business units and allows both teams to focus on what matters most.
• Stronger insights
  Internal control provides real-time input from the front lines. Internal audit contributes structured assessments and data-driven analysis. Combined, they offer leadership a more complete and accurate view of organisational risk.
• Better use of technology
  Shared tools—such as GRC platforms or common risk registers—support collaboration by enabling shared access to data, aligned risk taxonomies, and more efficient reporting.

When internal audit and internal control work together, controls are stronger, audits are sharper, and the organisation is quicker to react when something changes. People across the business, and outside it, start to trust the system more.

Where Synergy Happens: Key Areas of Collaboration

Collaboration between internal audit and internal control delivers the most value when it’s grounded in day-to-day reality. As we’ve already established, the two functions have different roles—but when they work together, like the two sides of the same brain or a guardsman and a detective sharing notes, they help the organisation spot risks sooner, act faster, and keep improving.

There are five key areas where that collaboration makes a real difference:

1. Risk assessment and prioritisation

Internal control teams—the guards on the ground—are close to daily processes and quick to notice when something starts to go off track. Internal audit, like the detective, has a broader view. They connect patterns across departments, identify deeper issues, and assess systemic risk. When both perspectives are combined, the organisation benefits from both proximity and perspective, just like the left and right hemispheres of a brain working together to assess a situation from multiple angles.

2. Coordinated planning and testing

Both sides often conduct testing, but without coordination, they risk covering the same ground. Internal control (the structured left hemisphere) works through routines and checklists. Internal audit (the analytical right hemisphere) builds its plans around strategic priorities. When they align, testing becomes more efficient, and the organisation avoids audit fatigue.

3. Sharing information and findings

A change in control procedures or an issue discovered by the audit team can’t stay in a silo. When communication flows freely, both sides get stronger. The guardsman alerts the detective to new activity on the ground. The detective reports back patterns or weaknesses that require a tactical shift. This back-and-forth allows each side to adjust and stay one step ahead.

4. Using common tools and language

A shared GRC platform, aligned definitions of risk, or even a unified taxonomy, make collaboration easier.

If the two “sides of the brain” don’t speak the same language, they can’t coordinate effectively. The same goes for audit and control—when their systems and terminology match, everything from risk reporting to follow-ups runs more smoothly.

5. Turning audit results into control improvements

Audit findings shouldn’t just sit in reports. They should trigger real changes in how the organisation works. When the detective shares new findings, the guardsman can adjust patrol routes, update protocols, and prevent the next issue before it appears.
 That’s how a healthy “organisational brain” learns: through a feedback loop that turns reflection into smarter action.

What Makes Synergy Work: Enablers of Success

Even the best intentions won’t create collaboration unless the right conditions are in place. Real synergy between internal control and internal audit needs structure, support, and above all, trust. When those elements come together, both functions can operate independently while reinforcing each other.

Here’s what makes that possible:

Support from leadership

Collaboration starts at the top. When senior leaders—especially the board and audit committee—actively support alignment between audit and control, it sends a message that working together isn’t optional, it’s expected. Think of it like the brain’s central command aligning its left and right hemispheres to respond to external threats. Without that coordination, reflexes slow—or fail.

Clear roles and responsibilities

To work together effectively, each function needs to know what it owns—and where the boundaries lie. This avoids overlap, confusion, and friction. Internal audit must maintain its independence, while internal control stays embedded in operations. The guardsman and the detective serve different purposes, but both rely on clarity: who investigates, who responds, and who acts on findings.

A culture of openness and respect

Collaboration thrives in organisations where transparency is valued. Control teams need to feel safe sharing concerns, and audit teams must approach their work as partners, not judges. When both sides trust each other, communication improves—and the feedback loop becomes a source of learning, not friction.

Shared systems and language

Using the same GRC platform, terminology, and reporting standards helps reduce misalignment and accelerates action. It also ensures that leadership sees a unified view of risk and performance. In a well-functioning “organisational brain,” signals don’t get lost in translation. The more seamless the connection, the faster the response.

When the basics are in place—clear responsibilities, trust, shared tools, and leadership support—collaboration happens more naturally. Internal audit and internal control stay focused on their roles, but they stay in sync. That’s what makes risk management more responsive and relevant to the business.

Different roles, same goal

According to Deloitte’s 2025 Internal Audit Outlook, internal audit is shifting—from a function focused primarily on assurance to one that delivers insight and foresight. But this transformation can’t happen in isolation. It depends on stronger integration with internal control, smarter use of data, and more collaborative ways of working.

As described earlier, these two functions work best when they’re in an ongoing conversation, like the two sides of the brain:

• Internal control is the left side of the brain, focused on structure and routine.
• Internal audit is the right side, stepping back to reflect, evaluate, and advise.

Or, when the former acts as the guardsman, close to the action, and the latter becomes the detective, spotting patterns others might miss.

Each has its role and strengths. However, when internal control and internal audit are in continuous dialogue—sharing insights, aligning efforts, and learning from one another—they create a smarter, faster, and more resilient approach to managing risk. And that’s what builds real trust in the whole system.