Harvest efficiency
Harvest efficiency is a mechanic for gathering and mining intended to regulate the amount of crafting materials you gain. Every gathering and mining node has a set harvest efficiency level. This level determines what your 
Gathering or 
Mining level should be to gain 100% of crafting materials.
- Any level below it decreases your yield by 5% (down to multiplying by 0.05 if you're 19 levels below Harvest efficiency level, it cannot drop to 0)
- Any level above it increases your yield by 5% (unlimited)
- This multiplier affects all types of material the node gives
| Gathering or Mining level
|
Yield multiplier |
|---|---|
| 1 | 0.05 (capped) |
| 10 | 0.05 |
| 20 | 0.5 |
| 30 | 1 |
| 40 | 1.5 |
| 50 | 2 |
| 60 | 2.5 |
If too low harvest efficiency pushes your yield under 1, it's possible to fail obtaining even basic materials. In this case, you do not get any Gathering or Mining experience, nor a chance to obtain standard or advanced materials.
Yield
All gathering and mining nodes use a set multipliers for basic materials and a set value for standard / advanced materials. This value reflects the amount of materials you get. (3 = 3 materials). Any bonuses multiply this value, including Harvest efficiency. Reaching any full number guarantees the item. Any remainder is then used as a roll chance (3.6 = 3 guaranteed materials with 60% chance to gain a 4th one). Same works for rare materials (node with a yield of 0.25 has a 25% chance to give you 1 material, otherwise you get nothing). Using a lot of bonuses can even make rare materials guaranteed with a chance to obtain more of them.