Book review: Practical Data Migration by Johny Morris

If I could only recommend one book to someone about to lead a data migration, it would be this one. Practical Data Migration by Johny Morris (published by BCS, The Chartered Institute for IT) is the book behind the PDM methodology – the same methodology I refer to as "PDM v3" in my post on the retail migration.

Why it's different

Most writing about migration gets stuck in the technology – ETL, tools, scripts. Morris flips that around. His central point is that data migration is a business problem, not an IT problem. IT can move bytes, but only the business knows what the data means, which of it is worth keeping and which is junk. That insight runs through the whole book.

What stuck with me

• The business owns the data. A migration succeeds or fails on the engagement of the people who actually use the data. The methodology builds that in with clear roles and "Key Data Stakeholders".
• Don't migrate everything. One of the most liberating principles: most legacy data doesn't need to come along. Actively deciding what not to migrate saves enormous amounts of time.
• Data Quality Rules. Capturing quality rules as concrete, measurable, owned artefacts – not as vague opinion – is something I've carried into every project.
• System Retirement Plans & landscape analysis. Understanding where the data comes from and where it's going before a single row is moved.

Who should read it?

Not just migration specialists. Project managers, data quality leads, ERP project owners and business people pulled into a transformation all get a lot out of it – precisely because it's written in business language rather than technical jargon. The third edition is updated and just as relevant today.

My takeaway

PDM is one of the cornerstones of how I work – my own refined 8-step method stands on its shoulders, and every time I pick the book up I find something to sharpen. If you want to understand why migrations fail – and how to get them right – start here.

You'll find the formal methodology at practicaldatamigration.com/methodology.