Master Data Cleaning: Identify Hidden Errors Affecting Analysis

Master Data Cleaning: Identify Hidden Errors Affecting AnalysisMaster Data Cleaning: Identify Hidden Errors Affecting Analysis

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Oreoluwa Oguntade

• Feb 10

The goal was to use this messy campaign dataset to demonstrate my data cleaning skills. 48 hours into it, I’m relearning the fact that visuals - PowerPoint presentations, or dashboard building - is how you show the work done behind the scenes. But here's what stood out while doing this task: Always go back to the basics.

I wanted to show stakeholders the campaigns that have had zero impact on conversions. However, my calculated measure returned a smaller value than I expected based on the total amount spent on the campaign, total clicks on the campaign, and total conversions generated by those clicks.

After writing and rewriting my DAX, I finally went back to my data, only to find a lone cell with a cost of $17.35 and a value of 0 in the conversions column. Meaning my DAX was never the problem.

powerbi dax dataanalysis

Geethasree Naguboina

pro

• Mar 6

Most spreadsheet problems are not Excel problems.

They’re structure problems.

I often see spreadsheets where:

• formulas reference half the sheet • headers change across tabs • logic is embedded inside long nested formulas • no one knows where the numbers actually come from

The result?

Small updates quietly break the entire model.

A simple structure solves most of this:

Raw Data → Processing → Output → Documentation

Raw data stays untouched. Processing handles the logic. Output shows only what decision-makers need. Documentation explains how metrics are calculated.

Clean structure reduces fragility and makes updates predictable.

Good spreadsheets aren't just about formulas. They’re about clear data flow and transparent logic.

Data Analysis exceldashboard businessinsights Data Visualization Microsoft Excel

Arman Tamboli

• Mar 6

Sales dashboard for client

Business Analysis Data Analysis Financial Analysis Microsoft Excel

Hayley Cantor

max

• Mar 5

Every time I open Powerpoint and start having a meltdown, I remind myself that I managed to build this in Powerpoint as a template for a client. Check it out