In 2006, if you were tasked with delivering a data migration, you had two choices: follow your employer’s proprietary internal process, or improvise. There was no publicly available, vendor-neutral methodology for the discipline. No shared language. No standard set of tools, roles, or governance structures. Data migration was, as Johny Morris would later put it, a field where “as an industry we are appalling.”
That year, Morris published the first edition of Practical Data Migration through the British Computer Society. It was the first non-proprietary methodology for enterprise data migration - and it quickly became what practitioners simply called “the bible.”
Twenty years in the making
The methodology did not emerge from a workshop or a research programme. It came from two decades of project delivery at major systems integrators - PwC, Logica CMG, CSC - where Morris led large-scale migration programmes across utilities, financial services, healthcare, manufacturing, and the public sector.
What he found, project after project, was that the same failures kept occurring. Not because of the technology. Not because of a lack of skill. But because of something structural: data migration projects were consistently framed as technical problems, when they were fundamentally business problems.
The Responsibility Gap - the no-man’s land between IT and business where data quality issues go to die - was not a personality clash or a project management failure. It was a structural inevitability of how projects were designed. And it was killing programmes that had every other ingredient for success.
PDM was built to close that gap.
What made it different
The first edition introduced four Golden Rules that remain unchanged today. Most methodologies of the era focused on the technical execution of migration - the ETL pipeline, the transformation logic, the load process. PDM insisted that none of that mattered if you got the business relationship wrong first.
Rule 1: data migration is a business issue, not a technical issue. Rule 2: the business knows best. Rule 3: no organisation needs, wants, or will pay for perfect data quality. Rule 4: if you can’t count it, it doesn’t count.
These were not platitudes. They were direct responses to the structural failures Morris had observed across dozens of programmes. Each rule addressed a specific, recurring failure mode.
From a book to a methodology
The first edition sold thousands of copies worldwide and established PDM as the primary text in the field. A second edition followed in 2012, introducing more structured processes and what attendees at the Data Migration Matters conference remember as “a large printed poster showing a process flowchart” - the first visual representation of the end-to-end PDM process.
PDMv3, published in 2020, reflected a changed landscape: cloud migrations, SaaS platforms, the ubiquity of Agile delivery, and a maturing market for data migration services. Two new chapters were added. The core principles were unchanged.
Today, PDM is recognised as the only industry-wide certified methodology for data migration - available to organisations, practitioners, and vendors alike. It is taught through the Hopp Academy online course and championed through the Data Migration Matters conference, the only European conference exclusively devoted to the discipline.
The gap that Morris identified in 2006 is still there, in projects across every industry. PDM exists to close it.