Reading Your EBV
After each genetic evaluation, every queen receives an EBV (Estimated Breeding Value) per trait. These scores reflect the queen's genetic potential, independent of the environment in which she was tested.
Reading the Scale
All EBV are normalised following the BeeBreed convention:
- Population mean = 100
- Standard deviation = 10
| EBV Score | Meaning | Population position |
|---|---|---|
| 120 | Two standard deviations above | Top ~2% |
| 110 | One standard deviation above | Top ~16% |
| 100 | Average | 50% |
| 90 | One standard deviation below | Bottom ~16% |
| 80 | Two standard deviations below | Bottom ~2% |
Concrete example
An EBV of 115 for honey means this queen's genetics produce roughly 15% more honey than the population average, after removing environmental effects.
The 8 Evaluated Traits
BeePass evaluates each queen on 8 traits, grouped into three categories:
Continuous Trait (BLUPF90+)
| Trait | Unit | Direction |
|---|---|---|
| Honey production | kg | Higher = better |
Ordinal Traits (THRGIBBS, scale 1-4)
| Trait | Scale | Direction |
|---|---|---|
| Gentleness | 1 (aggressive) → 4 (gentle) | Higher = better |
| Spring vigor | 1 (weak) → 4 (strong) | Higher = better |
| Wintering | 1 (poor) → 4 (excellent) | Higher = better |
| Non-swarming | 1 (swarms often) → 4 (never swarms) | Higher = better |
| Comb stability | 1 (unstable) → 4 (stable) | Higher = better |
Hygiene Traits (THRGIBBS, Pin Test)
| Trait | Measurement | Direction |
|---|---|---|
| HYG 6h | Cells cleaned out of 50 at 6 hours | Higher = better |
| HYG 24h | Cells cleaned out of 50 at 24 hours | Higher = better |
Where to See Your EBV
Your queens' EBV are displayed in two places:
- Queen F0 detail page — Evaluations tab, Breeding values section. Each trait is shown with its normalised EBV and reliability (r²).
- Index BeePass — The reference queen directory displays EBV to facilitate comparison across breeders.
Comparing Queens
When comparing two queens, look at:
- The EBV — The raw score (above 100 = above average)
- Reliability r² — A high EBV with low reliability is less certain than a moderate EBV with high reliability
- Number of traits — A queen excelling on a single trait but weak on others may not be the best overall choice
Important
Only compare EBV between queens from the same evaluation run. Reference means and standard deviations change from one run to the next.
See also:
- BLUP — Overview — Understanding the computation pipeline
- Reliability (r²) — Interpreting estimation accuracy
- Genetic Passport — The queen's complete identity