The Hidden Risk

Transformation programmes are usually designed around new capabilities, modern platforms, and improved customer experiences. But beneath every transformation sits a dependency that quietly shapes the entire outcome:

the data.

At TDMC, we’ve spent our careers inside complex enterprise estates, environments shaped by years of decisions, tactical fixes, overlapping platforms, and undocumented business logic. In these environments, data migration is rarely the headline risk, yet it consistently becomes one of the most influential factors in whether a transformation succeeds.

Industry research supports this pattern. Gartner reports that 83% of data migration projects either fail or exceed their budgets and timelines (Gartner, Data Migration: Best Practices for Success, 2021). Experian found that 84% of migrations are affected by poor data quality (Experian, Data Quality and Migration Trends, 2020). When migrations struggle, the transformation around them inevitably feels the impact.

As TDMC co‑founder Antony Selby puts it:

“In my opinion, data migration is one of the most underestimated risks in transformation. We work to make it predictable.”

This isn’t because teams lack capability. It’s because legacy data carries history and that history isn’t always visible at the start.

Early optimism hides deeper realities

Most programmes begin with momentum:

• target systems selected
• vendors aligned
• architecture defined
• delivery plans approved

In these early stages, legacy data is often treated as a manageable component, something that will be addressed once the new system is ready. But legacy data is rarely simple. It reflects years of operational behaviour, workarounds, and decisions that were never fully documented.

This is where hidden risk begins.

Documentation rarely tells the full story

Documentation describes how systems were intended to work. Data shows how they actually work.

Across dozens of migrations, TDMC has seen:

• fields used differently across systems
• values behaving inconsistently over time
• undocumented dependencies
• business logic embedded in data rather than code
• historical workarounds that became permanent
• divergent behaviours across markets or business units

These realities often remain invisible until teams interrogate the data directly.

The risk becomes visible late in the programme

Experian reports that 64% of data migration projects exceed their planned budget (Experian, Data Migration Benchmark Report, 2019). Bloor Research found that 73% of enterprise migration programmes fail to meet their stated objectives (Bloor, Data Migration Market Update, 2022).

These issues typically surface during:

• data quality checks
• reconciliation
• integration testing
• cutover rehearsal

As Antony explains:

“In my experience, many organisations only recognise the true data risk when cutover is close.”

By that point, timelines are fixed, dependencies are locked in, and options are limited.

TDMC changes the moment of truth

Our role is to shift the moment of discovery from late-stage pressure to early-stage clarity.

By making the risk visible, TDMC gives leaders the insight they need long before the pressure of cutover.

This is the foundation of predictable transformation.