data-storytelling

## Headline Formula Every data finding needs a headline: **[Specific Number] + [Business Impact] + [Actionable Context]**. "Readmission risk scores now flag 23% more high-risk patients, saving $2.1M annually." Not "We improved our model performance." Not "Results were statistically significant." The number makes it concrete. The impact makes it relevant. The context makes it actionable. ## Narrative Structures Pick the structure that matches the situation: | Structure | When to Use | Shape | |-----------|------------|-------| | Problem-Solution | Pitching new work | "Here's the gap, here's what we built" | | Trend | Status updates | "Here's what changed and why it matters" | | Comparison | Trade-off decisions | "Here are two options with costs" | ## Narrative Arc for Presentations **Hook** (the surprise or gap) → **Context** (what the audience needs to know) → **Evidence** (the data, 2-3 charts max) → **Implication** (so what?) → **Recommendation** (now what?) Start with the finding, not the methodology. Executives care about the answer. They'll ask about the method if they want it. ## Chart Selection Match the metric type to the right chart: | Metric Type | Chart | Example | |-------------|-------|---------| | Counts | Bar chart | Monthly patient encounters | | Rates over time | Line chart | 30-day readmission rate by quarter | | Part-of-whole | Stacked bar | Claim denials by category | | Distribution | Histogram or box plot | Length of stay distribution | | Correlation | Scatter plot | Cost vs complexity score | | Ranking | Horizontal bar | Top 10 diagnoses by volume | NEVER use pie charts. Stacked bar does everything a pie chart does, with readable labels. NEVER use dual Y-axes. Two metrics, two charts. Dual axes let you imply any correlation by scaling the axes. ALWAYS label data directly on the chart. A legend across the room is useless. ## Presentation Anti-Patterns **Charts without a "so what."** Every chart needs a headline that states the finding. "Figure 3: Revenue by Region" tells the audience nothing. "Northeast revenue dropped 12% after formulary change" tells them what to see. **Data dumps disguised as analysis.** 47 metrics on one slide helps no one. Pick the 2-3 numbers that matter and make them big. **Leading with methodology.** "We used a logistic regression with 47 features and cross-validated using..." Save it for the appendix. Lead with the result. **Hiding bad news in an appendix.** If the data tells an inconvenient story, put it up front. Credibility compounds faster than any dashboard metric. ## Cross-References For stakeholder alignment process (getting agreement on what to build), see `stakeholder-alignment`. For metric definitions (what exactly does this number mean?), see `metrics-definition`. This skill covers how to present the results.