Day 14: Power BI Dashboards & Reports

A Report is a multi-page document built in Power BI Desktop (.pbix) with interactive visuals, slicers, and drill-through — the primary deliverable for data analysts. A Dashboard exists only in Power BI Service and is a single page of tiles pinned from different reports or datasets. Dashboards are for executives who want a high-level summary from multiple sources on one screen. Reports are for analysts who need to explore data interactively. You cannot build a dashboard in Desktop — only in Service.

One question per page: each report page should answer one business question clearly. Visual hierarchy: put the most important metric top-left and largest. Consistent colours: use one colour per category consistently throughout. Minimal decoration: remove gridlines, borders, and chart titles that add no information. White space: give visuals room to breathe — do not pack every pixel. Mobile layout: consider how the report looks on mobile (View → Mobile Layout). Slicers at top or left: users expect filters in consistent positions. Performance: limit visuals per page to under 20 and avoid too many complex DAX measures on one page.

Drill-through lets users right-click a data point and navigate to a detail page filtered to that context. Create a new page → in the Filters pane, drag a field to the "Drill through" area (e.g. Product Name). This page now receives the product context when drilled to. Add visuals that show details for the selected product. Back button appears automatically. On the main report page: right-click any product data point → Drill through → your detail page. The detail page shows data filtered to only that product. Used for summary → detail navigation without making one page too busy.

Bookmarks capture the current state of a report page — which visuals are visible, filter states, slicer selections, and scroll position. Use cases: (1) Show/Hide panels: a button toggles a slicer panel visible/hidden using two bookmarks. (2) Scenario switching: buttons switch between "Revenue View" and "Profit View" using bookmarks with different measures visible. (3) Guided story: buttons advance through a presentation narrative. Create via View → Bookmarks panel → Add. Assign bookmarks to buttons: select a button → Action → Type: Bookmark → select the bookmark.

Performance Analyser (View → Performance Analyser → Start Recording) measures how long each visual takes to render — broken down into DAX query time, visual display time, and other time. After recording, each visual shows its render time. Long DAX query time indicates an inefficient measure. Long visual display time suggests too much data being rendered. Use it to: identify the slowest visuals on a page, optimise DAX measures that are taking too long, determine if DirectQuery is causing latency, and compare performance before and after optimisation.