Week 11 Notes

Lecture Objectives:

• Explain the different types of numbers used in BI application user interfaces.
• Correctly organize and display numbers into tables that suit how the numbers will be used.
• Correctly organize and display numbers into charts (graphs) that suit how the numbers will be used.
• Correctly organize tables and charts into reports and dashboard to effectively communication information to a business user.

Numbers

Can be divided mainly into three major groups:

• Quantities and categories
• Relationships within Categories
• Nominal
• Ordinal
• Interval
• Hierarchical
• Relationships between Categories
• Ranking
• Correlation
• Ratio
• Numbers that summarise
• Measure of Average
• Measures of Distribution
• Measures of money
• due to Inflation
• Currency conversion

Tables

Can be unidirectional or bidirectional.

Are used when we are presenting data in which need to look-up specific numbers, and there is more than a single unit of measure.

For good standardized table we follow the six Ehrenberg rules:

1. Round the numbers to two significant figures.
2. Use column and row averages to provide a focus point to the reader
3. Use columns to allows users to compare figures.
4. Order your columns and rows, either ascending or descending
5. You can use space to separate columns, to increase space between things which are not being compared
6. In case the numbers are important use a table, otherwise if shape is needed then a chart

Charts

A chart is used the shape of the data is important, and we want to show relationships between the  is the message not the numbers themselves. For example when we are trying to show the trend line

A few design rules are:

• Avoid chart junk, by increasing the data–ink ratio.
• Use small multiples to highlight comparisons and assess change
• Use complex graphs to portray complex patterns
• Relate graph size to information content
• Use graphical forms that promote comparisons
• Integrate graphs and text
• Know the audience

Pie Charts

Should be avoided because:

1. Humans are not good at comparing areas and angles.

2. The segment and clock position are perceived differently, causing misinterpretation.

Reports and Dashboards

Reports are meant to be more static and less interactive, whereas Dashboards are dynamic and meant to be very interactive.

Standard headers, footers, fonts, number and currency formats should be used for reports.

Dashboards are more focused on providing monitoring and measuring information to the user at a glance, hence, we need to take take advantage of pre-attentive processing, to allow better intuitiveness.