Data science that works

Data Science that Works

The common ask from a data scientist is the combination of subject matter expertise, mathematics, and computer science. However I’ve found that the skill set that tends to be most effective in practice are agile experimentation, hypothesis testing, and professional data science programming. This more pragmatic view of data science skills shifts the focus from searching for a unicorn to relying on real fleshand-blood humans. After you have data science skills that work, what remains to consistently finding actionable insights is a practical method of induction.

Induction is the go-to method of reasoning when you don’t have all the information. It takes you from observations to hypotheses to the credibility of each hypothesis. You start with a question and collect data you think can give answers. Take a guess at a hypothesis and use it to build a model that explains the data. Evaluate the credibility of the hypothesis based on how well the model explains the data observed so far. Ultimately the goal is to arrive at insights we can rely on to make high-quality decisions in the real world. The biggest challenge in judging a hypothesis is figuring out what available evidence is useful for the task. In practice, finding useful evidence and interpreting its significance is the key skill of the practicing data scientist—even more so than mastering the details of a machine learning algorithm.

The goal is to communicate about data science that works:

  • Start with a question.
  • Guess at a pattern.
  • Gather observations and use them to generate a hypothesis.
  • Use real-world evidence to judge the hypothesis.
  • Collaborate early and often with customers and subject matter experts along the way.

At any point in time, a hypothesis and our confidence in it is simply the best that we can know so far. Real-world data science results are abstractions—simple heuristic representations of the reality they come from. Going pro in data science is a matter of making a small upgrade to basic human judgment and common sense. This book is built from the kinds of thinking we’ve always relied on to make smart decisions in a complicated world.