DAX is the language of writing calculations in Power BI. We use DAX to write calculations such as year-over-year change and percentage, or percentage of the total or rank of customers by their yearly revenue. Writing calculations in DAX takes time, and you may likely need to re-use a calculation in multiple reports.
Creating copies of the PBIX file every time for reusing the calculation is not ideal. The better approach is to have a shared dataset created by DAX calculations and then create thin reports with live connections to the shared Power BI dataset. Using a shared dataset ensures that all the reports are using the same DAX calculations. If a change is needed, it is only needed in the shared dataset. Maintaining a solution like this would be much easier.
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