ADA - APY ROS Calculations

Understanding the Three Metrics

Pool Details now shows three different performance metrics, each answering a different question. They are not supposed to match, and the differences are meaningful.

1️⃣ Delegator Yield (APY)

What it answers

“If I delegate ADA to this pool, what annual return do I earn after costs?”

This is the delegator’s real yield.

What it includes

✔️ Fixed pool cost

✔️ Pool margin

✔️ Zero-block epochs (penalty)

✔️ Stake size effect

✔️ Annualized

What it excludes

❌ Pool pledge advantage

❌ Block luck normalization

Formula (conceptual)

For each epoch:

Then over N epochs:

73 epochs ≈ 1 year, so this is annualized

📌 Why lower than pool performance?

Because delegators pay costs and margin, and zero-block epochs hurt small pools the most.

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2️⃣ Pool Performance (ROS / ROA)

What it answers

“How efficiently does this pool convert stake into rewards?”

This is a raw performance metric — before delegator costs.

What it includes

✔️ Total pool rewards

✔️ Zero-block epochs

✔️ Annualized

What it excludes

❌ Fixed cost

❌ Margin

❌ Luck normalization

Formula

📌 Why higher than delegator yield?

Because this ignores fixed cost + margin — it’s the pool’s gross output.

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3️⃣ Luck-Adjusted Pool ROS (AdaStat)

What it answers

“How did the pool perform compared to what it should have earned?”

This is a fairness-normalized metric.

What it includes

✔️ Expected blocks (σ / sigma)

✔️ Network parameters (k, a₀, rewards)

✔️ Zero-block epochs

✔️ No operator cost effects

What it excludes

❌ Fixed cost

❌ Margin

❌ Delegator perspective

AdaStat logic

For each epoch:

Then:

Reported over fixed windows:

• 12 epochs

• 73 epochs (1 year)

• Lifetime (all epochs)

📌 This now matches your delegator APY closely — as it should.

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🔍 Why These Numbers Are Different (and correct)

Metric	Perspective	Costs	Luck-adjusted	Annualized
Delegator Yield	Delegator	✅ Yes	❌ No	✅ Yes
Pool Performance	Pool	❌ No	❌ No	✅ Yes
AdaStat ROS	Network-fair	❌ No	✅ Yes	❌*

* AdaStat is implicitly annualized via its own epoch windows.

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🧠 Key Insight (most important)

❗ Why your results “click”

• Delegator Yield ≈ AdaStat ROS

  → Both penalize unlucky epochs and small pool effects

• Pool Performance is higher

  → Ignores costs and fairness normalization

• Lifetime > ROS73

  → Early epochs were luckier than recent ones

This is exactly what AdaStat, PoolTool, and CExplorer show when interpreted correctly.

✅ Final takeaway (TL;DR)

• Delegator Yield = What stakers actually earn

• Pool Performance = Raw reward efficiency

• AdaStat ROS = Luck-corrected fairness score