Bad luck mitigation

Bad luck mitigation refers to any mechanic that adjusts the drop rate of certain rare items or other events to prevent particularly long dry streaks. This can be accomplished by increasing the chance of a drop after reaching some threshold, or by guaranteeing the drop on a specific kill count, among other methods.

Bad luck mitigation is motivated by the fact that most random drops are rolled independently, so individual kills do not guarantee progress towards the drop (referred to in statistics as being memoryless). Due to the nature of randomness, a small percentage of players would be expected to go dry on getting a drop, potentially several times over the drop rate. For example, a standard 1/100 drop only has a 63% chance of success after after 100 kills, while 1 in 1000 players would need more than 680 kills to receive the drop. To calculate this, use the following formula:

Probability

Number of kills for the 99.9th percentile:

→ →

Some drops will become guaranteed at a specific threshold, typically at the normal drop rate of the item or twice of it. These can only drop once per account, and most are not tradeable.

• Vorkath's head typically has a drop rate of 1/50 from Vorkath, but is a guaranteed drop on the 50th kill.
• Kq head is typically a 1/128 drop from the Kalphite Queen, but a Kq head (tattered) is guaranteed on the 256th kill, which is sufficient for completing the Elite Desert Diary.
• Hunters' Rumours require getting a special rare drop from each Hunter creature, which becomes a guaranteed drop after going twice the drop rate (e.g. a 1/20 drop is guaranteed on the 40th kill). Wearing the guild hunter outfit decreases the "pity threshold" count by 5%.
  • The enhanced quetzal whistle blueprint is a 1/50 drop from a hunters' loot sack, but an untradeable torn variant is guaranteed on the 100th rumour. This can be used to make the whistle for personal use, but cannot be sold. A torn perfected blueprint is also guaranteed after 250 rumours.
• During Raging Echoes League all echo equipment had a guaranteed drop at double the normal drop rate.
• The first dossier a player opens after reaching 100 Yama victories is guaranteed to drop the rite of vile transference if they have not received one already.
• The 25th Elite clue casket or 10th Master clue casket is guaranteed to be a Mimic if the player has not already encountered The Mimic.
• Slepey tablet typically has a drop rate of 1/25 from Phosani's Nightmare, but is guaranteed to drop on the 25th kill. Players that already have 25 kill count, without having the tablet present and without having used the tablet on the Drakan's medallion, will receive it on their next kill.

Rather than outright guaranteeing a drop after certain amount of kills, some drops will improve their drop rates with each kill, usually to a point where the drop becomes very common.

• Thread of elidinis initially has a 1/10 drop rate from Tombs of Amascut, but scales with the number of raid completions up to 3/10 after completing 15 raids. The rate is reduced to 1/50 after receiving the first thread.
  • The jewels for the Keris partisan follow a similar function, becoming about 3x more common as raid completions approach 75. They additionally have duplicate protection, so that each jewel is obtained at least once.
• The Forgotten Four's tablets and quartz all become more common as more kill count is achieved, until the first one is obtained, after which more tablets won't appear and quartz will revert to 1/200.
• Finding skilling pets becomes 15 times more likely after reaching 200 million experience in the corresponding skill. Before that point, the chance increases marginally with every level, following the formula where the base chance depends on the pet and activity.

Rather than using a single rare drop, splitting a reward into multiple more common drops has the effect of reducing the variance of the distribution without changing the expected (average) number of kills. This means fewer players will be extremely unlucky and go many times over the drop rate, but also means fewer players will be extremely lucky and get the drop early. Additionally, it allows players to make progress over a series of kills.

• Brimstone ring is made by combining 3 drops from hydras, rather than a single drop. The eye, fang, and heart are dropped in order, and are dropped sequentially without duplicates until all 3 have been obtained.
  • This also applies to the noxious halberd from Araxxor and the abyssal bludgeon from the Abyssal Sire.
• Venator bow is made by combining 5 venator shards, which are individually a 1/100 drop rather than a single, rarer drop.
• The Forgotten Four's vestiges progress in 3 stages of drops, with the first two drops giving the player a gold ring. Once it has been rolled 3 times, their respective vestige will drop.
• Yama drops oathplate armour pieces as well as shards to create the armour.

Some items that are all rolled from the same loot table, but are part of a set of items, will ensure the player completes the full set before allowing duplicate items to be dropped. This can greatly reduce the luck required to finish certain sets, as naturally getting the correct, different drop multiple times in a row is otherwise unlikely, such as at Barrows.

• The rewards chest from the Moons of Peril does not give duplicate pieces from a set until each piece in the set has been received at least once.
• The rewards chest from the Fortis Colosseum does not give duplicate pieces from the sunfire fanatic armour set until each piece in the set has been received at least once.
• When a piece of the pyromancer outfit is rolled, the player will always be given the piece they have the least of.
• The Guild hunter outfit, Lumberjack outfit, and Zealot's outfit will be obtained in a specific order without duplicate pieces.

• The Forestry Shop sells the rare untradeable fox whistle and golden pheasant egg for 75,000 anima bark each.
  • The Vale Research Exchange fulfils a similar purpose for the respective rewards from Vale Totems minigame.
  • The Abyssal lantern can also be bought from Apprentice Felix for 1,500 abyssal pearls, in case players do not obtain it from the Rewards Guardian.
• Some players may humorously refer to the Grand Exchange as bad luck mitigation.

• Drop rate
• Duplicates
• Calculator:Dry calc
• Kill count

v t e Mechanics
Engine	Java RuneScript RuneTek
Game clients	Jagex Launcher Desktop Mobile Third-party RuneLite HDOS Discontinued OSBuddy Konduit Java
Performance	Bad luck mitigation Cache format Clickbox Drop rate Game square Game tick Line of sight Player identification number Stealth
Exploits	Run trick Tick manipulation Tick eating Drop trick Animation stall
Graphics	Interface Graphical updates (historical)
Servers	Server Ping Lag