Power BI developers use Data Analysis Expressions (DAX) to create calculated measures for advanced analytics. They start by identifying key metrics, such as profit margins or growth rates, and use functions like CALCULATE, SUMX, or FILTER to perform calculations. Power BI developer ensure measures are optimized by minimizing the use of row-based operations. They leverage time intelligence functions, like SAMEPERIODLASTYEAR and DATESYTD, for trend analysis. Developers also use variables in DAX formulas to improve readability and performance. By testing and validating calculations, they ensure measures deliver accurate insights. These techniques enhance reporting with actionable metrics and KPIs.