Why we stopped building Power BI reports ourselves - and what actually worked

Our team tried to build Power BI dashboards in-house for about three months. We had two analysts who were comfortable with SQL and one junior developer who'd gone through a couple of online DAX courses. Seemed like enough on paper.

It wasn't.

The first set of reports looked decent - clean visuals, reasonable chart choices. But the numbers behind them were off. Not in a way you'd catch immediately. The kind of discrepancy that only surfaces when your CFO compares the dashboard margin figure against a manual spreadsheet and finds a gap of almost 11%.

The root cause turned out to be the data model. Our team had built everything on top of flat queries instead of a proper star schema. Every new measure we added either slowed things down or conflicted with existing calculations. We burned three weeks troubleshooting a year-over-year comparison that returned nulls for certain product categories - and it was a table relationship issue the whole time.

After that we decided to bring in external help. Found a team here https://cobit-solutions.com/en/services/power-bi-developers-for-data-driven-solutions/ and they rebuilt the data model in about ten days. Fixed the DAX measures, set up row-level security for different departments, and connected three sources — our ERP, CRM and a Google Sheet that marketing insisted on keeping.

What surprised me was how many business logic questions they asked before writing a single formula. Things like how we define an active customer, and whether product returns should reduce revenue in the month of the return or the month of the original sale. Those aren't technical questions. But getting the answers right changed the output significantly.

The reports run daily now. Everyone works from the same numbers. That alone was worth more than the cost.