Most analysis that goes wrong goes wrong in the first ten minutes, before anyone writes a single chart. A date column was read as text. A survey used minus one to mean no answer and the average quietly dropped. Two rows exist for every customer because of a join nobody checked. None of these are hard problems. They are easy to catch and almost impossible to notice later, once a dashboard is built on top of them and the number already looks reasonable.

The habit that separates analysts who get trusted from those who get corrected is simple. Before building anything, they spend the first hour getting to know the data on its own terms. Not exploring for insights yet, just establishing what they are holding and where it might lie to them. This article is that first hour, as a routine you can run on any dataset, in any tool, every single time.

Step one: get the shape

How many rows, how many columns, and what is one row. That last question is the most important one in analytics and the one beginners skip.…