Data Visualization

What are the three main ways to connect to data in Tableau?

Connect to a file (Excel, Text, JSON), connect to a server (Tableau Server, SQL), or connect to a saved data source extract.

What is a data source extract in Tableau?

A snapshot of your data optimized for performance, created automatically when you connect and define metadata types.

What is the difference between a join and a union?

Join: Combines tables horizontally (matching rows based on common fields).

Union: Combines tables vertically (stacking rows with the same structure).

What is data blending?

Combining data from multiple sources using a common field; one is the primary source (blue check), the other secondary (orange check).

What's the difference between dimensions and measures?

Dimensions: Qualitative, categorical fields (like Customer, Product, Date).

Measures: Quantitative, numeric fields (like Sales, Profit).

What color represents discrete fields in Tableau?

Blue

What color represents continuous fields in Tableau?

Green

What does encoding mean in Tableau?

Binding data elements to visual marks such as color, size, shape, label, or path.

What is a calculated field?

A new field created using a formula that combines or transforms existing fields.

What is a parameter used for in Tableau?

A dynamic input that allows users to replace constants in calculations, filters, or reference lines.

What is a context filter?

A primary filer that defines the subset of data for other dependent (nested) fiters

What types of marks can data be encoded with?

Color, size, shape, label, detail, tooltip, and path.

What is the function of a trend line?

To show a trend or pattern in data over time, often used in line charts.

What are common chart types for discrete categories?

Horizontal bar charts, bullet charts, and scatter plots.

What are common chart types for continuous data?

Line charts, area charts, histograms, and stacked bar charts.

What type of Tableau connection would you use to link directly to a live SQL database?

Server connection

When should you use a data blend instead of a join?

When data sources exist at different levels or come from different sources

Which field type affects the level of detail in a view?

Dimension

What is the purpose of aggregation in Tableau?

To summarize data (e.g., SUM, AVG) across dimensions for visualization.

In Tableau, what happens when you drag a field to the Color mark?

It encodes data values using different colors to distinguish categories or magnitudes.

What does a blue check mark next to a data source indicate?

It's the primary data source in a data blend.

How can you show both actual and target values in one chart?

Use a bullet chart

What chart type best shows data distribution?

Histogram

What is a hierarchy and how do you create one?

A drill-down structure of fields (e.g., Country → State → City), created by dragging one field onto another.

How can you export a Tableau worksheet to Excel?

Select the worksheet, then choose Export → Crosstab to Excel or Export Data to Excel.

What is data?

Data is an observation or measurement of a phenomenon, recorded as facts like time, temperature, or counts.

What are the four types of data measurement?

Nominal: Categories (e.g., product type)

Ordinal: Ordered categories (e.g., rank)

Interval: Equal distance between values, no true zero (e.g., temperature in °C)

Ratio: Equal distance with true zero (e.g., income, time)

What's the difference between continuous and discrete data?

Continuous: Can take any value (e.g., weight, temperature)

Discrete: Counted as distinct items (e.g., number of servers)

Who introduced the concept of graphical encoding?

Jacques Bertin

What are the 8 variables of visual encoding according to Bertin?

X-position, Y-position, Size, Value (lightness), Texture, Color, Orientation, Shape

What is the purpose of visual encoding?

Uses the intensity of a single color (light to dark) to represent quantity.

What does texture encoding represent?

Variation in visual density (e.g., dots, lines, or patterns) to differentiate categories.

What does orientation encoding do?

Uses angle or direction to differentiate values—easier to interpret than shape.

What's the difference between value and size?

Value: Refers to lightness or darkness (intensity).

Size: Refers to the physical area or magnitude of a visual element.

What are Edward Tufte's key principles of good visualization?

Show the data

Reveal detail at multiple levels

Make large datasets coherent

Encourage comparison

Integrate visuals with context (annotations)

Avoid "chartjunk"

What is the data-to-ink ratio?

The proportion of "ink" on a chart that represents actual data. High ratio = clear, efficient visualization.

What are sparklines?

Small, word-sized graphics showing trends in data alongside text.

What are elementary, intermediate, and overall questions*?

Elementary: Basic facts (e.g., how many sales in February?)

Intermediate: Relationships among groups (e.g., seasonal patterns)

Overall: High-level insights (e.g., overall performance trends)

Define mean, median, and mode.

Mean: Arithmetic average

Median: Middle value

Mode: Most frequent value

What does skewness in a distribution indicate?

Mean > Median: Positively skewed

Mean < Median: Negatively skewed

Mean = Median: Symmetrical

When should you impute missing data using the mean vs. the median?

Mean: For symmetric distributions

Median: For skewed distributions

What's the difference between data, information, and insight?

Data: Raw observations (measurements)

Information: Organized data that communicates meaning

Insight: New understanding or discovery based on data patterns

What type of data best describes "income level"?

Ratio

In Tableau, if a field represents "Product Category," what type of data is it?

Nominal (categorical)

What does "graphical encoding" mean?

Using visual properties (like color, size, and shape) to represent data

Which of the following is not one of Jacques Bertin's eight visual variables?

Font

Why is orientation often easier to interpret than shape?

Because differences in angle or direction are perceived more quickly and clearly by the human eye.

What is chartjunk according to Edward Tufte?

Any unnecessary or decorative visual element that does not convey meaningful information.

What is the purpose of the data-to-ink ratio principle?

To maximize data communication efficiency and reduce clutter.

What visualization type would you use to show distribution and detect skewness?

Box plot or histogram

What is the main difference between a histogram and a boxplot?

Histogram: Shows frequency across bins.

Boxplot: Summarizes data distribution into quartiles.

What does the "A" in RGBA color model represent?

Alpha channel, which measures opacity.

What is an insight in data visualization?

A new understanding or discovery drawn from analyzing visualized data

What is a dashboard?

A visual display of the most important information needed to achieve objectives, arranged on a single screen for quick monitoring (Stephen Few).

What are the critical aspects of a dashboard?

Single view of essential metrics

Monitored at a glance

Tailored to user context

Answers a question

Uses small, concise glyphs

What is the main purpose of a dashboard?

To answer a specific business question using key metrics and visuals that communicate insights clearly.

Why should you define the dashboard user first?

Because different users (CEO, manager, or team) need different levels of detail and metric focus — strategic, tactical, or operational.

What are common KPI categories in dashboards?

Industry Benchmarks, Cash Flow, Risk & Security, Customer Satisfaction, Asset Management, HR, Information Quality.

What is the design rule for metric placement?

Place the most important metric in the top-left or center area (highest visual value area).

What is a "glyph" in dashboard design?

A compact visual element (like a chart, icon, or symbol) that summarizes one or more metrics.

What are the main dashboard layout options in Tableau?

Fixed: Same size always

Range: Scales within defined limits

Automatic: Resizes dynamically with the window

What are layout containers used for?

To organize dashboard elements horizontally or vertically and control alignment, spacing, and padding.

What are good dashboard design guidelines?

Limit to 6 metrics or fewer

Use totals/summaries

Group related data

Use highlights for focus

Avoid clutter and 3D effects

What is meant by "dangerous visual territory"?

Overuse of 3D charts, excessive color, unnecessary gridlines, and chartjunk that distract from data.

What does intuitive view of information mean?

The audience should instantly understand the dashboard's message without needing analysis — the designer summarizes the insights.

What are interactive filters?

Tools that allow users to dynamically filter views by selecting data fields directly on the dashboard.

What is a highlighter in Tableau dashboards?

An interactive feature that highlights specific data points or categories when selected.

What are dashboard actions?

Interactive features that link views together — e.g., "Use as Filter," "Highlight," or "Go to another dashboard."

What is a dashboard jump?

A navigation object that allows users to click and move from one dashboard to another, often using text or images.

What is the purpose of annotations in dashboards?

To guide users by labeling actions — e.g., "Click to filter," "Hover for metrics," "Select category."

What are the recommended chart types for multiple discrete categories?

Bar tables, delta bar tables, mirror bars, bullet charts, and heat maps.

What are chart types for multiple ordered categories?

Bar tables and slopegraphs.

How should dashboards be designed for mobile devices?

Use automatic layouts to sync with the parent dashboard, or create independent phone layouts for more control.

What is the key takeaway from the dashboard summary?

Define the audience

Focus on key questions

Use visual hierarchy effectively

Highlight high-value metrics

Enable interactivity with actions

According to Stephen Few, a dashboard should be:

A visual display of the most important information needed to achieve objectives

What's the first step in designing an effective dashboard?

Define the target user and their information needs.

Which of the following layout types automatically resizes with the display window?

Automatic

Where should you place the most important metric on a dashboard?

Top-left or center (highest visual value area)

Why should dashboards limit the number of metrics to six or fewer?

To maintain focus and prevent cognitive overload.

What is a "glyph" used for in dashboards?

To summarize multiple metrics visually and compactly.

What does "Use as Filter" do in Tableau dashboards?

Makes a view interactive so selecting data filters other views.

What should you avoid in dashboard design?

3D charts, bright colors for excitement, unnecessary gridlines, and background decorations.

What is the benefit of interactive filters and highlights?

They let users explore data and identify patterns dynamically.

What is a dashboard jump used for?

To navigate between dashboards or link to external webpages.

What is Exploratory Data Visualization?

An analytical technique that uses visualizations to identify patterns, trends, and insights in data.

What role does animation play in data visualization?

It enables dynamic analysis, highlights anomalies, and allows viewers to mentally construct phenomena.

How is time typically encoded in visualizations?

Time is usually placed on the x-axis and progresses left to right.

What does bubble size represent in animated metric charts?

Population

What does color encoding represent in GAPMINDER visualizations?

Global regions.

What is the purpose of animated bar charts?

To show dynamic rankings over time with auto-sorting and branded color encoding.

What is the Hub-and-Spoke airline network model?

A design that routes passengers through central hubs, allowing flexible substitution during disruptions.

What is the Point-to-Point airline network model?

A design offering direct flights between smaller markets, but more vulnerable to cascading delays.

What is sonification in data visualization?

The use of sound to encode data, such as emotional states of markets.

What does the Mercator projection map help visualize?

Geographic positioning of data points like births, deaths, and colonial empires.

What is the difference between linear and logarithmic scales?

Linear scales increase by equal increments; logarithmic scales increase by powers of 10.

What does overplotting in geoplotting reveal?

Popularity of locations based on density of data points.

What makes animation engaging but not necessarily accurate?

Movement attracts attention but can distort perception if not carefully designed.

Which axis is most commonly used to represent time?

X-axis

What does animation allow in data visualization?

Analysis of multiple dimensions

In GAPMINDER, what does the Y-axis represent?

Life Expectancy