Blizzard Entertainment — StarCraft 2 Ranked System

Overview

StarCraft II's ranked ladder was one of the game's core competitive systems, defining how millions of players measured skill, tracked progress, and earned recognition. As Lead UX Designer, I led the player experience for the ranking system, partnering with engineering and data science to shape each major iteration. We replaced the traditional numeric rating model with seven visual leagues, transforming competitive ranking into a stronger sense of identity while making progression easier to understand, celebrate, and aspire toward.

A dark comparison graphic titled Competitive Ranking Systems, comparing how Chess and StarCraft II represent competitive players. On the left, a photo of Magnus Carlsen, World Chess Champion, with his rating: 2,850. On the right, a photo of Joona 'Serral' Sotala, World StarCraft II Champion, with his league: Grandmaster. — Unlike chess, which communicates competitive standing through a numeric rating, StarCraft II represents it through visual leagues.

Seven League Progression

Players progressed through seven visual leagues—Bronze, Silver, Gold, Platinum, Diamond, Master, and Grandmaster—creating a clear path from beginner to the highest levels of competition.

League icons representing each tier in the StarCraft 2 ranked system — Each league provided a distinct visual milestone from Bronze through Grandmaster.

The Challenge

StarCraft II's ranked play was experiencing player churn. Research revealed distinct player populations with different needs. Highly skilled players wanted rankings that accurately reflected their ability, while less experienced players needed enough positive reinforcement to keep playing.

Cross-Functional Validation

Qualitative research, quantitative analysis, and cross-functional collaboration shaped each iteration before player behavior validated the results.

Three Ranking Models

Each major release tested a different hypothesis. Findings from one model informed the next, moving the ranked system from population-based distribution to skill-based progression and ultimately to persona-driven design.

Iteration 1

Population-Based Tiers

The initial design distributed the first five tiers evenly by population. Each tier held 20% of players, with Master and Grandmaster reserved for the top 3%. Players responded positively, finding the distribution fair and easy to understand. This became the baseline.

A dark, polished distribution diagram shaped like a bell curve, divided into six colored bands representing the initial population-based tier design: Bronze at 20%, Silver at 20%, Gold at 20%, Platinum at 20%, Diamond at 17%, and a combined Master and Grandmaster band at the exclusive top 3%. A vertical axis label reads Player Population and a horizontal axis label below the chart reads Player Skill. Each band is labeled with its league name and percentage along the top of the chart, connected by a colored guide line that extends down to just above the curve. — Population-based distribution. Five equal 20% bands across the skill curve, with Master and Grandmaster reserved for the top 3%.

Iteration 2

Skill-Based Tiers

Qualitative feedback and MMR (Matchmaking Rating) analysis revealed that the league distribution no longer aligned with the underlying skill curve. Bronze and Silver contained too many players while Gold had too few. As those players improved, the league structure wasn't providing progression that reflected their actual development.

I redesigned the league distribution around the skill curve, reducing the size of Bronze and Silver while expanding Gold.

A dark, polished distribution diagram shaped like a bell curve, showing the redesigned skill-based tier bands: Bronze reduced to 10%, Silver at 20%, Gold expanded to 30%, Platinum at 20%, Diamond at 17%, Master at 2%, and Grandmaster at 1%. Upward and downward triangle markers next to Gold and Bronze call out the expansion and reduction. An editorial callout in the upper-left corner, titled What Changed, notes that Bronze was reduced from 20% to 10% and Gold was expanded from 20% to 30%. A vertical axis label reads Player Population and a horizontal axis label below the chart reads Player Skill. Each band is labeled with its league name and percentage, connected by a colored guide line that extends down to just above the curve. — Skill-based distribution. Gold expands to 30% of the player base. Bronze drops to 10%.

Iteration 3

Persona-Driven Design

Even after the skill-based redistribution, engagement problems persisted in Bronze and Silver. Continued analysis pointed to a more specific problem. Players in different tiers had fundamentally different motivations and responded to different things, which meant grouping by skill alone still wasn't enough.

I led the analysis that produced four data-driven player personas.

Competitors

Motivated by competitive accuracy. Rank needs to reflect true skill, and even minor inflation erodes trust in the system for this group. Master and Grandmaster, top 5%.

Climbers

Value meaningful, accurate skill progression. Advancement milestones are what keep this group playing, so the design shows clear progress indicators when a tier boundary is within reach. Platinum and Diamond.

Hobbyists

Feel competent and broadly satisfied, but not driven to advance. Progression indicators are intentionally vague to keep players feeling competent without pressuring them to advance. Gold.

Casuals

High drop-off risk. This group responded more to winning than to rating accuracy, so the design uses a wins-based progression model where players advance on wins alone and can move up with a win rate below 50%. Bronze and Silver.

A dark, polished distribution diagram shaped like a bell curve, showing the final persona-driven tier bands: Bronze at 3%, Silver at 17%, Gold at 40%, Platinum at 20%, Diamond at 17%, Master at 2%, and Grandmaster at 1%. An editorial callout in the upper-left corner, titled What Changed, notes that Bronze was reduced from 10% to 3% and Gold was expanded from 30% to 40%. A vertical axis label reads Player Population and a horizontal axis label below the chart reads Player Skill. Colored guide lines beneath each league name extend down to just above the curve. Below the chart, four colored bracket groups visually cluster the seven leagues into the four player personas: Casuals spanning Bronze and Silver, Hobbyists spanning Gold, Climbers spanning Platinum and Diamond, and Competitors spanning Master and Grandmaster, while each individual league band remains visible above. — Persona-based distribution. Seven tiers grouped into four design targets. Each persona receives a distinct progression model.

Result

The final system gave each persona a distinct progression model. Casuals used wins-based advancement rather than rating accuracy, which required separating their ranking logic from the rest of the ladder. Upper tiers remained purely skill-based, preserving competitive integrity for Competitors. Gold held at 40%, anchoring the Hobbyist population at the center of the curve where most players sit.

Impact

Quantitative Outcomes

Quantitative results measured against the prior major release and validated by internal data science teams.

+40%

User retention in ranked play

Recognition

I was invited as a guest speaker to the Wharton School of Business by Professor Kevin Werbach for his course "For the Win," on game design principles and behavioral motivation systems.