(old) Guide to RNG

Foreword

If your first thoughts on seeing the words ‘Guide’ and ‘RNG’ together were something along the lines of “Is this for real?” then you’re certainly not alone. For me, what initially started out as just a few ideas for a blog post has slowly evolved into this.

While people may find themselves wondering how much you can really write about random numbers my experience in putting this together has been the opposite. Once I got started I quickly found myself overwhelmed with topics I wanted to include. The biggest challenge has actually been deciding what to cut to keep the guide to a respectable length.

That’s probably another thing worth bringing up – I’ve called it a ‘Guide’ but I might as well have gone ahead and called it a ‘Rant’ or ‘Poorly Bound Collection of Ramblings’. I havent really approached it with the aim or expectation that people will actively seek out it’s contents, but rather to invite discussion on RNG and to create something that people might refer a misguided friend or guildmate toward.

I’ve long held a passion for statistics, in particular chance and probability, and I sincerely hope I’m able to share some of that with you in the list of topics I’ve decided to include.

-Saate

Table of Contents

1 – [What is RNG and how does it effect you?]
2 – [Common mistakes in dealing with RNG]
                  – [Mistake #1 – Assuming that Random is Fair]
                  – [Mistake #2 – Assuming that Random Remembers]
                  – [Mistake #3 – Miscalculating or ignoring the odds of an event]
                  – [Mistake #4 – Looking for patterns where none exist]
3 – [Superstition and Mythology]
                  – [Examples]
                  – [The Law of Large Numbers]
4 – [The role of an individual’s perception and awareness]
5 – [How WoW uses chance]
6 – [Calculating Odds]
                  – [Using probability to your advantage]
7 – [Further Reading & External Links]

1. What is RNG and how does it effect you?

I think it would probably be in order for me to start with the basics before we move on to the harder stuff. Within World of Warcraft the term ‘Random Number Generator’ (RNG) is used to refer to any random chance based event.

The outcome of any random chance event is referred to as RNG. If a player performs a random /roll the results – good or bad – are generally attributed to the RNG. If a player loses a roll for the 10th time in a row he or she might exclaim ‘Damned RNG!’ as a way of blaming their bad luck. Likewise RNG gets the credit for flukes and other statistical anomalies – for example three players rolling against each other all rolling 100 might be met with a cry of ‘Thats RNG for you’.

So when I say this is a “Guide to RNG” what I really mean is “Guide to randomness as it applies to the World of Warcraft”. Clear as mud? Great, let’s move on!

Why you should read this

Time is a precious commodity too readily thrown away. A fundamental step toward success is the careful and precise allocation of our time toward achieving worthwhile objectives. It is imperative, then, that one has a good comprehension when it comes to determining the odds or likelihood of an event occurring. If I was asked to provide just one reason for putting this together then saving time would be it.

Study the information here, ask questions, and above all invest your time well.

2. Common mistakes in dealing with RNG

If you frequent WoW economic blogging sites and forums you may have seen the term ‘freetard’ come up.

This is a pejorative term used to refer to people who, being ignorant of opportunity cost (link), mistakenly believe that if they farm materials themself the item is free of cost. Here I’d like to expand on this and demonstrate how a poor understanding of chance can, and does, frequently lead people to waste ridiculous amounts of time.

I’ll also share many stories of frustration born out of these situations. (RNGtard)

Mistake #1 – Assuming that Random is Fair

“Random does not remember, and random does not care”

Random does not equal fair. If an item has a 10% chance of dropping then probability states that it should take ten kills to see the item drop once. In practice this will not be the case for everyone. Some people will see the item drop ten times from ten kills and some people will not see the item drop at all in twenty kills.

This is completely normal. This is what random means.

People often make the mistake of assuming that ‘random’ means ‘fair and even distribution’. If I flip a coin 10 times and get 10 heads it’s not a sign that something is broken – it’s a sign that random is working as intended!

Mistake #2 – Assuming that Random Remembers

Past random events do not influence future ones. If you were unlucky enough to kill a boss 20 times for a 10% drop, and didnt get it, then on your 21st time killing the boss your chance of getting the item is….exactly the same as it always was at 10%.

If you’re farming a 1% drop, for example the Baron’s Mount, then statistically it should take 100 kills to see 1 drop. The odds of it dropping remain the same, however, no matter if it’s your 1st kill or your 100th kill.

Mistake #3 – Miscalculating or ignoring the odds of an event

This one absolutely kills me. People who choose to ignore statistics and probability at the cost of their time. I can’t tell you how many times over the years I’ve cringed at hearing what someone was ‘farming’ – let me make a few honorable mentions:

• A guy farming a very specific area and creature for a world drop item. Having checked wowhead for where it dropped and seeing every single creature of a specific level on the ‘dropped by’ table he proceeded to go and farm the one that dropped it .00002% of the time over the one that dropped it .00001% of the time.
• A guy on the forums who reckoned that since the four items he was farming had drop rates of 12%, 15% 20% and 25% he had a 72% chance of getting at least one.
• The fellow who reasoned that since he’d killed the baron 21 times so far his chances of having the mount drop soon were ‘getting better’.

Mistake #4 – Looking for patterns where none exist (trends?) (same as #2)

In statistics (citation needed) this mistake is also known as ‘Gamblers Fallacy’. This is the belief that in a chance based event a particular outcome may be ‘due’ based on previous outcomes. Imagine a situation in which someone flips a coin three times and gets three consecutive heads, then imagine someone saying “I’m going to call tails, because tails is due” and thats what I’m on about.

You might know people in real life who regularly gamble. Have you ever heard them say “I’m due for a big win” after a losing streak? People seem to take an almost superstitious view towards finding these patterns and insist they exist and keep wasting their money!

Superstition and Mythology

“A Superstition is the irrational belief that future events are influenced by specific behaviors, without having a causal relationship.”

Human beings don’t handle the concept of ‘random’ very well, it’s a fact (link) proven time and time again throughout history. Through something called ‘confirmation bias’ our brains are programmed to remember what works and forget what doesnt.

What ends up happening? People don’t handle events with a smaller rate of occurance (ie lower drop rate) very well. Volumes of lore, mythology and superstition spring up around them to attempt to bring reason to them.

Take a look at the pre-nerf Baron’s Mount, the [Deathcharger's Reigns]. This was once a 1 in 10,000 event based on data collected. In the absence of official word speculation was rife with theories on how to make it drop.

“You need to have someone in your group that’s exalted with the Argent Dawn. It increases the drop chance.”

Someone thinks it, someone hears it and repeats it, and all of a sudden the masses believe it. These mythologies are unfactual, unscientific, unofficial and difficult to test (ie disprove).

The terrible thing in all of this is that true facts and information are uncovered this same way. This means that from time to time some developing myth may be found to be steeped in truth and the myth-makers revel in this and use it to support other myths. (Link to PFLAG issue)

[Characteristics of a Mythology - DIAGRAM]

Myth Busting

http://forums.worldofwarcraft.com/thread.html?topicId=20143779139&postId=200525401286&sid=1#10

“I killed over 60,000 of the correct fireflies trying to get a firefly pet no pet drop still. I killed over 15,000 emerald whelpings a few months ago in hopes for a tiny whelping.”
Armory (ie actual data) says no.

Finally, the ultimate damning evidence comes if we treat the reported information as genuine and calculate the odds of this occuring.

One in one hundred septillion chance of occuring
Ten Million Players

(A) 100,000,000,000,000,000,000,000,000
(B) 10,000,000

A/B = 10^19
10,000,000,000,000,000,000

So if the WoW playerbase were ten quintillion times larger than it currently is and if EVERY single one of those players went out and killed 60,000 mobs trying to farm the captured firefly we might see this.

Once.

• Drop rate of approximately 0.01% (1 in 1,000)
• Total mobs killed is 60,000
• 0.999^60000 = 0.000000000000000000000000008498% chance of having occured.

So there we have it! Either we have some embellishment here or this gentleman has beaten odds of 1 in 100,000,000,000,000,000,000,000,000

Odds are 1 in 100,000,000,000,000,000,000,000,000

http://www.wowarmory.com/character-statistics.xml?r=Frostwolf&cn=Eightbit&gn=Bubblegum+Tigers

203 Baron Runs, No Mount – How likely?

In WoW, there have been issues raised concerning raid loot generation, given statistically unlikely sequences of loot being dropped for the same raid leader.
Are they actually looking at hard data with reasonable sample sizes?

The Law of Large Numbers

“A principle of probability called the Law of Large Numbers shows that an event with a low probability of occurrence in a small number of trials has a high probability of occurrence in a large number of trials.”

– Random does not equal fair
– Calculating odds of an event
- Examples of people ‘farming’ world drops
– Odds are not cumulative – (adding drop rates together)
– Past events do not influence future ones
– Flip a coin example, diagram of all possible outcomes

3. The role of an individual’s perception and awareness

“Random does not remember, and random does not care”

I’ve got a feeling this topic might be difficult to properly talk through. What I want to try to get across here is how the role of the individual (ie you) in percieving chance is driven largely by your awareness.

What’s that mean? Random isn’t fair, random is random, and when our brains get in the way and start looking for patterns to try to explain it things get messed up. Imagine if I was to tell you that

– last 10 times you’ve turned the television on it’s been an ad break
– traffic lights
– going on a holiday overseas and running into a friend. You might think to yourself afterwards ‘what are the odds of that happening?’ and think it remarkable. However prior to the event occuring you had not been considering ‘what are the odds ill run into someone’.

– The law of large numbers, Aman’thul daily example not coming up (1 in 12)
– true ‘random’ datasets from atmospheric noise. Examine each of them as generated and discuss what the impacts of those sets on a person farming a 1% drop might have been. YouTube this and/or include in talkthrough?

4. How WoW uses chance

– Switch from boss drops (tier 0,1,2) to token drops (3+)
– Switch from TF/Sulfuras drops (classic) to Atiesh/Valanyr fragments (BC+)

4.a Calculating Chance

5. Examples of the application of chance

– Using opportunity cost to decide if something is worth farming
– Raptor farming. Diagrams, data sets, spreadsheet and essay on viability
– Price setting

6. Further Reading & External Links

Terra Nova: Superstition in MMO’s http://terranova.blogs.com/terra_nova/2006/10/superstition.html
The Daedalus Project: Superstitions http://www.nickyee.com/daedalus/archives/001554.php

Conspiracy theorist versus WoW RNG http://yamz.wordpress.com/2009/05/22/a-theory-on-the-rng-factor-in-wow/

– Books
– Other links