Algorithm Details
Delve into the methodology and factors that constitute our metagame health analysis.
The MtG Health Index is an analytical tool designed to provide an objective, data-driven snapshot of the metagame health for various Magic: The Gathering formats. We believe that a "healthy" metagame is not defined by a single metric but is rather a composite of several interacting factors.
Our goal is to quantify these factors using publicly available Magic: The Gathering tournament data. By tracking these metrics over time, we aim to identify trends, understand the impact of new set releases or bannings, and offer a nuanced perspective on the state of each format.
It's important to remember that this index is a model. While it's built on quantitative data, the interpretation of "health" can be subjective, and different players may weigh these factors differently. This tool provides one consistent way to look at format dynamics.
This factor assesses metagame balance through a weighted average of three components. Historical Distribution (40% weight) compares the current archetype breakdown against the stable 5-year average for that format. The 90-Day Baseline (40% weight) compares against a dynamic baseline (an Exponentially Weighted Moving Average of recent data), rewarding stability relative to its recent identity. Conceptual Balance (20% weight) compares the current state to a theoretically perfect 33/33/33 split between Aggro, Control, and Combo.
Score Meaning: A score of 100 indicates the metagame is very similar to its long-term average, its recent norms, and a perfect conceptual balance. A low score indicates a format that has deviated significantly from one or more of these benchmarks.
Formula: Final Score = 100 * (1 - WeightedDissimilarity). WeightedDissimilarity = (0.40 * D_Historical) + (0.40 * D_Baseline) + (0.20 * D_Ideal). Each component (D) is a Bray-Curtis Dissimilarity score: D = (Σ |Pi - Qi|) / (Σ (Pi + Qi)). D_Historical compares Current vs. 5-Year Average. D_Baseline compares Current vs. 90-Day EWMA (EWMA_t = α * P_t + (1-α) * EWMA_{t-1}). D_Ideal compares Current vs. an ideal [33.3, 33.3, 33.3] balance.
Why it Matters: By using a long-term historical average as an anchor, a dynamic recent baseline to measure short-term shifts, and an ideal balance as a theoretical check, this factor provides a robust view of metagame stability. It can identify formats that are suddenly changing, have drifted into an unhealthy state over time, or remain consistently balanced.
A composite score providing a holistic view of format diversity. It combines two key perspectives in equal measure: the variety of decks being played (Metagame Deck Diversity) and the concentration of individual staple cards across those decks (Metagame Card Diversity). This approach ensures a format is evaluated on both strategic variety and card-level originality.
Score Meaning: A score of 100 represents a vibrant, diverse metagame with many viable strategies and card choices. A score of 0 indicates a stale, 'solved' format dominated by a few decks and mandatory staple cards.
Formula: Final Score = (Metagame Deck Diversity Score * 0.5) + (Metagame Card Diversity Score * 0.5)
Deck Diversity Score: (H / H_max) * 100 - (σ * 5.0)
H(Shannon Index) =-Σ(p_i * ln(p_i))wherep_iis the metagame proportion of decki.H_max=ln(S)whereSis the total number of unique decks.σis the standard deviation of all deck percentages, penalizing top-heavy metagames.
Card Diversity Score: Calculated from the Herfindahl-Hirschman Index.
- Herfindahl-Hirschman Index =
Σ(p_i²) * 10,000, wherep_iis a card's play rate proportion. - The final score is a tiered conversion of this index, rewarding lower concentration.
Why it Matters: A healthy format needs both deck diversity (many viable strategies) and card diversity (freedom in card choices within those strategies). This index captures both, identifying metagames that are either 'solved' (low deck diversity) or 'homogenized' (low card diversity).
This factor tracks the trend in the number of recorded tournament events. Unlike a simple linear score, this metric uses an asymmetric curve that heavily rewards stability. A format with zero growth is considered very healthy (score of ~85), with diminishing returns for high growth and a steep drop-off for any decline in participation.
Score Meaning: A score of ~85 indicates a stable number of events (0% growth). The score rapidly approaches 100 for positive growth and steeply falls towards 0 for negative growth, reflecting that decline is a stronger negative signal than growth is a positive one.
Formula: Let g be the avg. monthly growth %. If g >= 0, Score = 85 + 15 * (1 - e^(-g/7.0)). If g < 0, Score = 85 * e^(g/7.0).
Why it Matters: Sustained or stable event participation is a strong indicator of a thriving, popular format. This model correctly identifies stability as healthy and is highly sensitive to declining interest, providing an early warning sign of potential format issues.
This factor assesses the trend in player participation using the same asymmetric model as event growth. A stable player base (0% growth) receives a high score of ~85. The score is very sensitive to declines in player numbers, which are penalized more heavily than gains are rewarded.
Score Meaning: A score of ~85 indicates a stable player base. The score approaches 100 for growth and falls sharply towards 0 for decline. This reflects that a shrinking player base is a more critical health concern than a growing one is a boon.
Formula: The score is the average of the Paper and MTGO growth scores, which are calculated independently. For each, let g be the avg. monthly growth %. If g >= 0, Score = 85 + 15 * (1 - e^(-g/7.0)). If g < 0, Score = 85 * e^(g/7.0). Final Score = (Score_Paper + Score_MTGO) / 2.
Why it Matters: Player engagement is the most direct indicator of a format's appeal. This model rewards formats that retain their players and provides a strong negative signal if a format is bleeding its player base, which is often a critical sign of poor health.
This factor measures the diversity among the top-performing decks over a sustained period (e.g., the last 12 months). It looks at how many different decks consistently reach the #1 spot in tournaments based on aggregated monthly win data from publicly available Magic: The Gathering tournament results. If only one or two decks dominate the top position month after month, this score will be lower. Conversely, if a variety of decks share the top spot over time, the score will be higher. A healthy metagame ideally sees a range of strategies succeeding at the highest competitive level, preventing stagnation and promoting a dynamic play environment.
Score Meaning: 0 indicates maximum dominance by very few decks, while 100 suggests maximum diversity among the top-performing decks.
Formula: Score = 100 * (1 - (Σ(months_at_#1_i)^2 / 144)). This score rewards a lower sum of squared months at #1 for each dominant deck.
Why it Matters: High dominance by a few decks can lead to a stale metagame, reduce player engagement, and may indicate an imbalance that could require intervention (like bannings). A good score suggests a balanced and competitive top tier.
This factor provides a composite score based on two economic indicators: card demand and overall affordability. It begins by calculating a 'basket price' for each format, which is a 50/50 average of the format's top 25 most-played cards on MTGO and in paper (Cardmarket). This basket price is then used to derive the final score.
Score Meaning: A high score indicates a format with healthy, growing demand and reasonable affordability, suggesting it's accessible and desirable. A low score can indicate either collapsing demand (crashing prices) or an extreme price barrier for new players.
Formula: Final Score = (Demand Score * 0.5) + (Affordability Score * 0.5)
Healthy Card Demand Score: Based on an asymmetric curve on the 30-day price growth rate (g).
- If g >= 0:
Score = 85 + 15 * (1 - e^(-g/7.0)) - If g < 0:
Score = 85 * e^(g/7.0)
Overall Card Affordability Score: Based on inverted logarithmic normalization against the global price range.
Normalized = (ln(CurrentPrice) - ln(GlobalMax)) / (ln(GlobalMin) - ln(GlobalMax))Score = 1 + (Normalized^0.75 * 99)
Why it Matters: The economic health of a format is crucial for its long-term sustainability. This index captures the balance between a format being popular enough to drive demand and affordable enough to attract new players.
This factor incorporates the AI-generated sentiment score from the most recent Banned & Restricted announcement analysis. It reflects the AI's assessment of the announcement's likely impact on the format's future health.
Score Meaning: The score is directly used, ranging from 1 (very pessimistic outlook) to 100 (very optimistic outlook), with 50 being neutral. If no relevant B&R analysis is available, the score defaults to a neutral 50.
Formula: This score is generated by a large language model and does not have a mathematical formula. It is based on a qualitative analysis of the B&R announcement text.
Why it Matters: B&R announcements are major events that directly address format health. This factor provides a forward-looking, qualitative measure to complement the other quantitative metrics, capturing the potential impact of bans, unbans, or even the significance of no changes.
Each of the individual health factors described above contributes to an overall Final Health Index for the format. This final score is calculated as a weighted average of the individual component scores.
The current weights are approximately:
- Metagame Archetype Distribution: 15%
- Metagame Diversity Index: 20%
- Monthly Event Count Growth: 15%
- Player Growth (Combined Paper/MTGO): 15%
- Winner Deck Dominance: 15%
- B&R Health Score: 10%
- MtG Card Price Health: 10%
Formula: Final Score = (Archetype * 0.15) + (Diversity * 0.20) + (Price * 0.10) + (EventGrowth * 0.15) + (PlayerGrowth * 0.15) + (Dominance * 0.15) + (B&R * 0.10)
These weights reflect our current assessment of the relative importance of each factor, but they may be adjusted in the future as the model evolves or community feedback is incorporated.
The Final Health Index provides a single, at-a-glance measure, but we strongly encourage users to explore the individual component scores to gain a deeper understanding of the specific dynamics affecting a format's health.