Data Storytelling and Visualization

The Chart Nobody Understood

In the previous lesson, we explored writing slides that communicate. Now let’s build on that foundation. A data analyst presented quarterly results to the leadership team. She’d built a beautiful chart: a dual-axis combination of bar and line graphs showing revenue, costs, margins, and growth rates across twelve months, broken down by four product lines, with color-coded trendlines.

The chart was technically perfect. It contained every piece of relevant data. And not a single person in the room could interpret it in the three seconds it was on screen.

Data visualization in presentations isn’t about showing all the data. It’s about showing the right data in a way that communicates one clear insight immediately.

The Data Storytelling Framework

Every data point in your presentation should follow this sequence:

CONTEXT → DATA → INSIGHT → IMPLICATION

1. Here's why you should care about this number
2. Here's the number
3. Here's what it means
4. Here's what we should do about it

Example:

• Context: “We’ve been investing heavily in customer retention this year.”
• Data: “Our retention rate went from 72% to 91%.”
• Insight: “That’s the highest retention rate in our industry. We’ve gone from average to best-in-class.”
• Implication: “This means our CAC recovery period dropped from 14 months to 8, which changes the math on everything we’re planning for next year.”

Use AI to build data stories:

I have this data point for my presentation:
[the number or chart you want to present]

Context: [why this data was collected/why it matters]
Audience: [who's in the room]

Build a data story:
1. What context should I set before showing the data?
2. How should I present the data itself?
3. What's the insight—the "so what?"
4. What's the implication for my audience specifically?
5. How can I make the number tangible?
   (Anchor to something they understand)

Choosing the Right Chart

Not all charts are created equal. Each type communicates a specific kind of relationship.

The Chart Cheat Sheet

When in doubt:

I want to show: [describe the data relationship]
The key insight is: [what should the audience take away]

What chart type would communicate this most effectively?
Why? And what should I label/highlight to ensure the
audience sees the insight immediately?

The One-Chart-Per-Slide Rule

Just like one idea per slide, use one chart per slide. Two charts on a slide split attention. If you need to compare two charts, show them on sequential slides and highlight the comparison verbally.

Making Numbers Stick

Raw numbers are abstract. The human brain didn’t evolve to process statistics. It evolved to process stories, images, and comparisons.

Technique 1: Anchor to the Familiar

“$3.6 billion” means nothing to most people. “$3.6 billion—enough to buy every home in Vermont” means something.

I need to make this number meaningful: [your data point]
My audience is: [who]

Give me 5 ways to anchor this number:
1. Physical comparison (size, weight, distance)
2. Time comparison (how long, how often)
3. Per-person or per-unit breakdown
4. Comparison to something familiar to this audience
5. An analogy that makes the scale visceral

Technique 2: The Before/After

Don’t show a number in isolation. Show what changed.

“Our response time is 2.3 minutes” is information. “Our response time went from 14 minutes to 2.3 minutes” is a story.

Quick check: Before moving on, can you recall the key concept we just covered? Try to explain it in your own words before continuing.

Technique 3: The Human Scale

Whenever possible, connect data to people.

“We processed 1.2 million transactions” is abstract. “That’s 1.2 million people who got their results while they were still in the doctor’s office instead of waiting three weeks” is human.

Technique 4: The Comparison

Put your number next to something else.

“We achieved 99.9% uptime” sounds good. “While our competitor averaged 94% uptime—that’s 26 more hours of downtime per year—we achieved 99.9%.” Now the audience understands what 99.9% really means.

Designing Data Slides

Declutter Relentlessly

Default chart settings in most software add unnecessary elements: gridlines, borders, legends, axis labels, decimal places. Remove everything that doesn’t directly support the insight.

Before decluttering: A chart with gridlines, both axes labeled, a legend box, data labels on every bar, a colored border, and a title that says “Chart 1.”

After decluttering: A chart with a headline stating the insight, one subtle axis for reference, direct labels on the key data points, and nothing else.

Highlight the Insight

Use color, size, or annotation to draw the eye to the data that matters.

If you’re comparing five products and Product C is the star, make Product C a bold color and everything else gray. The audience immediately sees where to look.

My chart shows: [describe the data]
The key insight is: [what the audience should notice]

Suggest how to visually highlight the insight:
1. What color strategy would draw the eye?
2. Should I annotate anything directly on the chart?
3. What elements can I remove to reduce clutter?
4. Should I add any reference lines or benchmarks?

The Big Number Slide

Sometimes the most powerful data slide isn’t a chart at all. It’s a single number, large on the screen, with a one-sentence interpretation.

┌─────────────────────────────────────────┐
│                                         │
│                  23%                    │
│     Revenue growth in 6 months          │
│                                         │
└─────────────────────────────────────────┘

This works when the number itself is the story. Let it breathe. Don’t surround it with other data.

Common Data Presentation Mistakes

Exercise: Transform a Data Slide

Take a data-heavy slide from an existing presentation (or create one with sample data).

1. Identify the single insight the data supports
2. Write a headline that states the takeaway
3. Choose the right chart type
4. Declutter: remove everything unnecessary
5. Highlight the key data point
6. Write the “so what?” and implication for speaker notes
7. Create an anchor that makes the number tangible

Key Takeaways

• Data without interpretation is an assignment, not a communication
• Follow Context → Data → Insight → Implication for every number
• Choose chart types based on the relationship you’re showing, not habit
• One chart per slide, just like one idea per slide
• Make numbers stick by anchoring to familiar things, showing before/after, humanizing, and comparing
• Declutter charts relentlessly and use color to highlight the insight
• Sometimes the best data slide is just one big number with one sentence

Next lesson: presenting to different audiences. How to adapt your style, depth, and approach.