Understanding and fixing blank values in Power BI

Blank values are a common issue in Power BI reports, and they can be frustrating to fix. In this tutorial, Mitchell Pearson from Pragmatic Works explains why blanks appear in your data, how to identify the source of the issue, and how to fix it effectively. This post summarizes the key points from the video and provides solutions to common blank value problems in Power BI.

What Causes Blank Values in Power BI?

Blank values can occur for several reasons, but the most common causes include:

• Missing Attributes in the Dimension Table: If the dimension table that describes the data does not have all the necessary attributes (e.g., missing hospital facility IDs), it can lead to blanks in the report.
• Data Integrity Issues: Sometimes, blank values appear because the data is incomplete, even though it exists in the dimension table.

Identifying the Source of Blank Values

Mitchell provides a detailed example using a report showing the average spending per hospital by state. In this example, blank values appear because the facility ID for some hospitals is missing from the dimension table. To identify the source of the blanks:

• Right-click on the blank value and select "Show Data Point as a Table" to view related data.
• Check whether the missing attribute exists in the dimension table. If it does not, you'll need to update your data model.

How to Fix Blank Values in Power BI

There are two main ways to fix blank values in Power BI:

• Fix the Source Data: The best solution is to fix the data at the source. This involves adding the missing facility IDs or other attributes to the database, third-party vendor systems, or other data sources.
• Quick Workaround Using Power Query: If you cannot fix the source data, Mitchell demonstrates a workaround using Power Query Editor. Here's how:
1. Go to the Power Query Editor and create a new table with the missing attributes (e.g., missing facility ID).
2. Append the new table to your existing dimension table using the "Append Queries" option.
3. Apply the changes and check whether the blanks are fixed.

Handling Data Integrity Issues

Another common reason for blanks is missing data in the dimension table. If the facility ID exists but other attributes, like the state, are missing, this will also result in blank values. To fix this:

• Go to the Power Query Editor and add the missing attributes (e.g., state) to the new table.
• Ensure that all relevant columns have data to avoid missing values in the report.

Best Practices for Handling Blank Values

While the workaround provided in the video is useful for quick fixes, it's not a long-term solution. Here are some best practices:

• Always aim to fix the data at the source whenever possible.
• If you're using a workaround, regularly check the data for updates to avoid duplication or missing data.
• Use the "Remove Duplicates" option in Power Query if necessary to clean up the data.

Conclusion

Blanks in Power BI reports are a common challenge, but once you understand the underlying causes, fixing them becomes straightforward. Whether it's missing data in the dimension table or incomplete records, Mitchell Pearson provides clear steps to resolve the issue efficiently. By applying these solutions, you can enhance the accuracy and completeness of your Power BI reports.

If you want to dive deeper into Power BI, Pragmatic Works offers live boot camps and training sessions that can help you become proficient in data modeling and report building. Check out our full training options!

Don't forget to check out the Pragmatic Works' on-demand learning platform for more insightful content and training sessions on Power BI and other Microsoft applications. Be sure to subscribe to the Pragmatic Works YouTube channel to stay up-to-date on the latest tips and tricks.