Hockey Stick Chart

A hockey stick chart shows a long period of relatively flat activity followed by a sudden, steep rise—so named because the plotted line resembles a hockey stick. It is used across fields to illustrate dramatic inflection points, from scientific measurements (e.g., temperature or medical results) to business metrics like sales or user growth.

Anatomy of the chart

• Blade: the initial flat, low-activity segment.
• Inflection (the bend): the point where growth accelerates.
• Shaft: the long, steep upward trend that follows.

Typically the x-axis represents time and the y-axis represents the measured quantity (sales, temperature, cases, etc.).

Where it appears

• Science and public policy — examples include global temperature records and epidemiological measurements.
• Business and startups — sudden adoption, viral growth, or rapid revenue expansion can create a hockey stick pattern.
• Social science — measures such as poverty rates or other indicators that change rapidly after a tipping point.

Interpreting a hockey stick pattern

A pronounced rise draws attention, but the pattern alone doesn’t explain causes or sustainability. Key questions to ask:
* Is the increase durable or a short-term aberration (seasonality, one-off events, data errors)?
* What are the drivers behind the inflection (product-market fit, marketing spend, regulatory change, technology)?
* Does rapid top-line growth translate to profitability or healthy unit economics?
* Could small baseline values make proportional changes appear more dramatic?

Careful analysis of underlying data, time horizons, and accompanying financial or operational metrics is essential before drawing conclusions from the visual alone.

Business example: Groupon

Groupon’s early revenue trajectory illustrates a classic hockey stick shape:
* 2008: under $100,000 in sales (blade).
* 2009: about $14.5 million (early rise).
* 2010: $312.9 million (inflection).
* 2011: $1.6 billion (shaft).

Despite explosive revenue growth, Groupon reported large net losses (for example, a $413 million loss in 2010) driven by heavy selling and marketing expenses—showing that steep revenue increases don’t automatically mean profitability.

Key takeaways

• A hockey stick chart highlights a dramatic change after a period of little activity.
• It’s a useful visual for identifying inflection points, but requires investigation into causes and sustainability.
• In business contexts, examine profitability and unit economics alongside growth to avoid misleading conclusions.