Documentation standards in Power BI - Dashboard Guide

Dashboard Mode - Documentation standards

Dashboard Goal

This dashboard demonstrates best practices for documenting Power BI reports clearly and effectively. It helps users understand the data sources, calculations, and visuals used.

Sample Data

OrderID	Product	Category	Sales	Quantity	OrderDate
1001	Notebook	Stationery	120	4	2024-01-15
1002	Pen	Stationery	45	10	2024-01-16
1003	Chair	Furniture	300	2	2024-01-17
1004	Desk	Furniture	450	1	2024-01-18
1005	Marker	Stationery	60	5	2024-01-19

Dashboard Components

• KPI Card: Total Sales
  Formula: Total Sales = SUM(Sales[Sales])
  Shows total sales amount: 975
• KPI Card: Total Quantity Sold
  Formula: Total Quantity = SUM(Sales[Quantity])
  Shows total quantity sold: 22
• Bar Chart: Sales by Category
  Shows sales split between Stationery (225) and Furniture (750)
• Table: Detailed Sales Data
  Shows all rows from sample data with columns OrderID, Product, Category, Sales, Quantity, OrderDate
• Documentation Text Box
  Explains data source, calculation logic, and visual purpose for user clarity

Dashboard Layout

+---------------------+---------------------+
|  KPI: Total Sales   | KPI: Total Quantity |
|       (975)         |        (22)         |
+---------------------+---------------------+
|      Bar Chart: Sales by Category          |
|          Stationery: 225                    |
|          Furniture: 750                     |
+--------------------------------------------+
| Documentation Text Box                      |
| Explains data source and calculations      |
+--------------------------------------------+
| Detailed Sales Data Table                   |
| Shows all sample rows                       |
+--------------------------------------------+
    

Interactivity

Adding a slicer for Category filters the bar chart, KPI cards, and detailed table simultaneously. Selecting "Furniture" updates total sales to 750, total quantity to 3, and shows only furniture rows in the table.

Self Check

If you add a filter for Category = Stationery, which components update and what are their new values?

• KPI Cards update: Total Sales = 225, Total Quantity = 19
• Bar Chart updates to show only Stationery sales
• Detailed Table shows only Stationery rows
• Documentation Text remains unchanged

Key Result

A Power BI dashboard demonstrating clear documentation standards with KPIs, bar chart, detailed table, and explanatory text.

Practice

1. Why is documentation important in Power BI reports?

easy

A. It hides data from users.

B. It increases the file size of the report.

C. It makes reports easier to understand and maintain.

D. It automatically fixes errors in data.

Solution

1. Step 1: Understand the purpose of documentation

   Documentation helps explain what the report does and how it works.

2. Step 2: Identify the benefit in Power BI context

   Clear documentation makes reports easier to use and maintain by others or yourself later.

3. Final Answer:

   It makes reports easier to understand and maintain. -> Option C

4. Quick Check:

   Documentation improves clarity = A [OK]

Hint: Documentation = easier understanding and maintenance [OK]

Common Mistakes:

• Thinking documentation changes report size
• Believing documentation hides data
• Assuming documentation fixes errors automatically

2. Which of the following is the correct way to add a comment in a DAX formula in Power BI?

easy

A. # This is a comment

B. // This is a comment

C.

D. /* This is a comment */

Solution

1. Step 1: Recall DAX comment syntax

   DAX uses double slashes (//) for single-line comments.

2. Step 2: Compare options with DAX syntax

   Only // This is a comment uses // which is correct for DAX comments.

3. Final Answer:

   // This is a comment -> Option B

4. Quick Check:

   DAX comments start with // = B [OK]

Hint: DAX single-line comments start with // [OK]

Common Mistakes:

• Using # which is for other languages
• Using HTML style comments
• Using /* */ which is not valid in DAX

3. Given this DAX measure with a comment:

SalesAmount = SUM(Sales[Amount]) // Total sales amount

What will be the output of this measure in a report?

medium

A. The sum of sales amounts plus the comment text

B. The text 'Total sales amount'

C. An error because of the comment

D. The sum of all sales amounts

Solution

1. Step 1: Understand how comments affect DAX measures

   Comments are ignored by the DAX engine and do not affect calculation.

2. Step 2: Evaluate the measure logic

   The measure sums the Sales[Amount] column values, so output is total sales amount.

3. Final Answer:

   The sum of all sales amounts -> Option D

4. Quick Check:

   Comments ignored, measure sums values = A [OK]

Hint: Comments do not affect measure output [OK]

Common Mistakes:

• Thinking comments become output text
• Assuming comments cause errors
• Believing comments add to calculation

4. You wrote this DAX measure:

Profit = SUM(Sales[Revenue]) - SUM(Sales[Cost]) // Calculate profit

But Power BI shows an error. What is the likely cause?

medium

A. The column names might be misspelled or missing.

B. DAX does not support comments at the end of a line.

C. You cannot subtract two SUM functions in DAX.

D. The comment syntax is incorrect in DAX.

Solution

1. Step 1: Check comment syntax validity

   The comment syntax // is valid in DAX, so comments are not the cause.

2. Step 2: Consider common errors in measure formulas

   Errors often come from misspelled or missing column names in SUM functions.

3. Final Answer:

   The column names might be misspelled or missing. -> Option A

4. Quick Check:

   Check column names first for errors = D [OK]

Hint: Check column names first when measure errors occur [OK]

Common Mistakes:

• Blaming comment syntax for errors
• Thinking SUM subtraction is invalid
• Assuming comments can't be inline

5. You want to document a complex Power BI report for your team. Which combination of documentation practices is best?

hard

A. Use clear names for tables and columns, add comments in DAX, and write descriptions for visuals.

B. Only add comments in DAX formulas; names and descriptions are optional.

C. Use vague names but add many comments in visuals only.

D. Skip comments and rely on team meetings to explain the report.

Solution

1. Step 1: Identify good documentation practices

   Clear names, comments, and descriptions help everyone understand the report easily.

2. Step 2: Evaluate options for completeness

   Use clear names for tables and columns, add comments in DAX, and write descriptions for visuals. combines all good practices: naming, commenting, and describing visuals.

3. Final Answer:

   Use clear names for tables and columns, add comments in DAX, and write descriptions for visuals. -> Option A

4. Quick Check:

   Combine naming, comments, descriptions = C [OK]

Hint: Combine clear names, comments, and descriptions for best docs [OK]

Common Mistakes:

• Relying only on comments or only on names
• Using vague names that confuse users
• Skipping documentation and relying on meetings