Data Contracts

Foreword

I still remember when Chad Sanderson first started writing about data contracts, back when the concept was brand new and the data world was still figuring out ideas like “shift left” and data quality.

Around that time, I was also friends with Mark Freeman, an up-and-coming, brilliant data engineer who was also mentoring part-time. When Chad and Mark became friends, I knew something great was going to happen.

When I first heard that Chad and Mark were writing a book on data contracts, I was both curious and a bit envious. Curious, because the topic sits right at the intersection of everything we wrestle with daily as data professionals, namely trust, communication, and accountability. Envious, because I knew they’d articulate what so many of us have felt for years but struggled to put into words: that the biggest challenges in data aren’t purely technical, but mostly human.

For too long, we’ve treated data quality as a downstream problem to be fixed by “the data team.” Data teams have built monitoring systems, observability dashboards, and clever duct tape patches that help us react more quickly when something breaks. Data debt keeps piling up. However, as this book demonstrates, none of that addresses the underlying issue. At its core, data quality relies on how effectively people communicate across teams. We nerds forget this. This communication depends on how clearly expectations are defined, how change is managed, and how responsibility is shared. In other words, it’s ...