Your Dashboards Are Pretty, But Are They True? The Power BI Competency Gap.
Power BI has democratized business intelligence. It empowers organizations to connect to hundreds of data sources, transform raw data into coherent models, and create beautiful, interactive dashboards that can be shared with anyone. When used correctly, it is a powerful engine for creating a data-driven culture.
But this accessibility is also its biggest trap. In the hands of a developer who only knows how to drag and drop visuals onto a canvas, a Power BI report is not a source of truth; it's a beautifully designed lie. You get dashboards that are slow, show incorrect numbers, and are impossible to maintain. The "self-service" dream becomes a "self-service" nightmare of data chaos and distrust.
An analyst who can make a bar chart is not a Power BI expert. An expert understands the difference between a calculated column and a measure. They can write complex DAX (Data Analysis Expressions) to answer sophisticated business questions. They can design a robust and performant data model using star schema principles. They can implement row-level security to ensure that users only see the data they are authorized to see. This playbook explains how Axiom Cortex finds the developers who possess this deep, systemic understanding of business intelligence.
Traditional Vetting and Vendor Limitations
A nearshore vendor sees "Power BI" on a résumé and assumes competence. The interview might involve asking the candidate to create a simple visual. This superficial approach fails to test for the critical skills that separate a professional BI developer from a casual user.
The predictable and painful results of this flawed vetting process are common:
- The DAX Disaster: A dashboard is filled with measures that give incorrect results because the developer does not understand filter context, the most fundamental concept in DAX. The sales team's "Year-to-Date Revenue" is off by 20%, and no one knows why.
- The "Model from Hell": The data model is a tangled mess of dozens of tables connected in a "snowflake" schema, with bi-directional relationships everywhere. The result is a model that is slow to query and produces ambiguous results.
- Performance Nightmares: A dashboard takes minutes to load because the developer has used calculated columns where measures were needed, or has imported massive, un-summarized tables instead of using DirectQuery or an aggregated model.
- Governance Gaps: There is no row-level security. Every user can see all the data, including sensitive HR and financial information, creating a massive internal data breach risk.
The business impact is a complete failure to achieve a return on your BI investment. You have a beautiful BI tool, but you have no business intelligence. Your organization loses faith in data and reverts to making decisions based on gut feel and spreadsheets.
How Axiom Cortex Evaluates Power BI Developers
Axiom Cortex is designed to find the BI professionals who think like data architects and business analysts, not just like report builders. We test for the practical, deep skills that are essential for building enterprise-grade BI solutions with Power BI. We evaluate candidates across four critical dimensions.
Dimension 1: Data Modeling and Power Query
A robust and performant data model is the foundation of any good Power BI solution. This dimension tests a candidate's ability to ingest, clean, and model data effectively.
We provide candidates with a messy set of data sources and evaluate their ability to:
- Clean and Transform Data with Power Query: Can they use the Power Query editor to perform complex data transformations, handle errors, and merge data from different sources?
- Design a Star Schema: A high-scoring candidate will immediately talk about organizing the data into a star schema, with a central fact table and surrounding dimension tables. They can explain why this is critical for performance and usability.
- Choose the Right Storage Mode: Can they explain the trade-offs between Import, DirectQuery, and Composite models?
Dimension 2: DAX Mastery
DAX is the formula language of Power BI. A developer who is not fluent in DAX cannot answer complex business questions. This is the single biggest differentiator of a senior Power BI developer.
We give them a data model and ask them to write DAX measures to answer specific questions. We evaluate if they can:
- Understand Filter Context: Can they explain what filter context is and how it affects the result of a calculation? Can they use functions like `CALCULATE` to manipulate the filter context?
- Write Time Intelligence Functions: Can they write DAX measures for common time-based calculations, like year-to-date, month-over-month, and same-period-last-year comparisons?
- Optimize DAX Performance: Can they use tools like DAX Studio to analyze the performance of their measures and identify bottlenecks?
Dimension 3: Visualization and Report Design
This dimension tests a candidate's ability to turn a data model into a clear, intuitive, and actionable report.
We evaluate their ability to:
- Choose the Right Visual: Can they choose the most effective visual for a given piece of data? Do they understand when to use a bar chart vs. a line chart vs. a scatter plot?
- Design for Usability: Do they design reports that are clean, uncluttered, and easy for a business user to understand? Do they use features like bookmarks and drill-through to create interactive experiences?
Dimension 4: Governance and Administration
An enterprise BI platform requires strong governance. This dimension tests a candidate's understanding of how to manage and secure a Power BI environment.
Axiom Cortex assesses how a candidate would:
- Implement Row-Level Security (RLS): Can they design and implement a dynamic RLS model to ensure users only see the data they are authorized to see?
- Manage Workspaces and Apps: Can they design a strategy for organizing content in workspaces and distributing it to users via Power BI Apps?
From a Charting Tool to a Business Intelligence Platform
When you staff your analytics team with Power BI developers who have passed the Axiom Cortex assessment, you are investing in a team that can deliver true business intelligence, not just pretty pictures.
A retail client was struggling with a collection of disconnected and untrustworthy Power BI reports. Using the Nearshore IT Co-Pilot, we assembled a BI pod of two elite nearshore Power BI developers.
In their first quarter, this team:
- Built a Centralized, Certified Dataset: They created a single, master data model in Power BI that served as the "single source of truth" for all sales and inventory data.
- Developed a Suite of Standardized Reports: They built a set of clean, fast, and reliable reports on top of this certified dataset for different business functions.
- Empowered Self-Service Users: They trained the company's business analysts on how to connect to the certified dataset to build their own reports safely, without having to worry about data modeling or DAX.
The result was transformative. For the first time, the entire company was making decisions based on the same, trusted set of numbers. The analytics team was freed from data wrangling and could focus on generating insights.
What This Changes for CTOs and CIOs
Using Axiom Cortex to hire for Power BI competency is not about finding a tool expert. It is about insourcing the discipline of professional business intelligence development. It ensures that your BI platform becomes a strategic asset that drives data-driven decision-making, rather than a source of confusion and distrust.