1) The document discusses predicting the addictiveness and lifetime of online games using player behavior data and facial electromyography measurements of emotions. 2) An addictiveness index is defined based on the decline rate of the ratio of player presence over time, and facial muscle activity is measured to quantify emotional responses to different games. 3) A model is created relating emotional strength measurements to addictiveness indexes with 94% accuracy, and is validated with 11% average error rate at predicting addictiveness of unseen games. This could help optimize game development and investment decisions.

1. Forecasting Online Game
Addictiveness
NetGames 2012
Jing-Kae Lou National Taiwan University
Kuan-Ta Chen Academia Sinica
Hwai-Jung Hsu Academia Sinica
Chin-Laung Lei National Taiwan University

2. World of Warcraft by Blizzard

3. World of Warcraft by Blizzard
4.5 years and $63M USD for development before
release on 2004*
*http://digitalbattle.com/2006/06/15/world-of-warcraft-cost-63-million/
**http://online.wsj.com/article/SB10001424052748703467304575383443343071562.html?mod=googlenews_wsj
> $37M USD for upkeep and expansions during
2004 to 2010**

4. Online Game Industry is Competitive
$1M to $200M USD
dev cost per game*
> 200 game titles
each year**
*http://www.gamesetwatch.com/2007/04/mmo_production_costs_how_low_c.php
*http://www.gamespot.com/news/star-wars-the-old-republic-cost-200-million-to-develop-6348959
**http://www.gamespot.com/

5. The Terrifying Truth
Most of them survived
only 4--9 months.
http://www.slideshare.net/TomSente/casualconnect2012-honeytracks-game-lifecycle-kpis
Usually long before a game’s investment could ever be paid off…

6. Are All Games Equally Cloud-Gaming-Friendly? / Kuan-Ta Chen 6
The Question
Is a game’s lifetime
predictable?

7. Are All Games Equally Cloud-Gaming-Friendly? / Kuan-Ta Chen 7
In other words …
Is a game’s addictiveness
predictable?
addictiveness [noun]:
the ability to retain players active in the
game for a long time.

8. Are All Games Equally Cloud-Gaming-Friendly? / Kuan-Ta Chen 8
The Significance
STOP developing hopeless games
SUGGEST better design decisions during
development
CHOOSE better games to publish (for game
publishers)

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State-of-the-Practice
Intuition of game designers
Feedbacks from focus groups
Psychologically inspired methods
E.g., the think aloud method
Subjective and thus
tends to be biased

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Our rationale
- Being entertained
- Having various emotions arisen, e.g.,
joy, excitement, tension
Why a player addicts to
an online game?

11. Are All Games Equally Cloud-Gaming-Friendly? / Kuan-Ta Chen 11
Our Approach
Prediction
Model
Lab emotion
studies
Lab emotion
studies
An unpublished
game X
Performance
on market
Performance
on market
An unpublished
game X
Published games

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GROUNDTRUTH DATASET
DESCRIPTION

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Our Collaborator
Gamania, the no. 1 game company in Taiwan
Gamania released player session information
(every player’s login and logout events) of 11 games to us

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Overview of Games
4 ACT
2 FPS
5 RPG

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Account Activity Records (AAR)
AAR Format
Dataset Overview

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QUANTIFYING GAME
ADDICTIVENESS

17. Are All Games Equally Cloud-Gaming-Friendly? / Kuan-Ta Chen 17
Attempt #1: Subscription period
Subscription period
The time span (in days) of a player’s first and last game
sessions.
Issues
The actual time players spent in game is not considered.
INTUITION
A game is more addictive if its gamers tend
to play it as much as they can.

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Attempt #2: Ratio of Presence
Ratio of presence (RoP)
The total number of days that the gamer entering the game
at least once during the subscription period.
E.g., Entering the game on 20 days with 100 subscription
period  RoP = 20/100 = 0.2
Issues
Bias toward games with short subscription periods
E.g., average 4 online days over 5 subscribed days = RoP 0.8

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Subscription period and RoP

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RoP(OP)
RoP with a certain observation period
RoP curve
The curve formed by RoPs over a range of OP
RoP Generalization

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The RoP curve of FPS2
RoP curves follow a power-law
relationship with OP.

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Defining Addictiveness Index
β
The decline rate of RoP over time
genre-independent

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MEASURING PLAYER EMOTION

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Corugattor supercilli muscle groups
FrowningNegative EmotionNegative Emotion

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Zygomaticus major muscle groups
Smiling

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Facial EMG approach
1. Continuous emotion measures (can be at a rate of 1000
Hz or even higher)
2. Does not disturb game play
3. Objective since the emotional indicators are directly
measured rather than told by subjects
(EMG: Electromyography)

29. Are All Games Equally Cloud-Gaming-Friendly? / Kuan-Ta Chen 29
Facical EMG Measurement Setup
Corrugator Supercilii
muscle
Negative emotions
Zygomaticus Major
muscle
Positive emotions

30. Are All Games Equally Cloud-Gaming-Friendly? / Kuan-Ta Chen 30
Measurement Devices
PowerLab 16/30
Electrodes
Wires

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Measuring Facial EMG during
game play

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Experiment Design
84 subjects are asked to play the 11 games
A subject must be new to the games he played
Each game session lasts >= 45 minutes continuously

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Quantifying the Measurement
EMG samples are taken at 1,000 Hz, so a 45-minute
trace comprises
45 × 60 × 1, 000 = 2, 700, 000 samples
The average absolute differences between adjacent
samples is taken as the representative index
Given a time series of electrical potential samples P = {p1, p2, …, pn}
CS: corugattor supercilii muscles  negative emotion
ZM: zygomaticus major muscles  positive emotion

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35. Are All Games Equally Cloud-Gaming-Friendly? / Kuan-Ta Chen 35
FORECASTING GAME
ADDICTIVENESS

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Emotion vs. Addictiveness

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Modeling Game Addictiveness
ES: the emotional strength
ES = CS + ZM
The combined emotional strength arisen
β = ω0 + ω1∙CS + ω2∙ZM + ω3∙CS:ZM + ω4∙CS:ES
+ω5∙ZM:ES Adj. R2
= 0.94

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Leave-One-Out Validation
Pearson cor: 0.86
Kendal cor: 0.78
Avg. error rate: 11%

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Applications of the model
Early evaluation of game design
Market value assessment before publishing
1. Optimize the odds of successful investments
2. Target more accurately the provision of better
entertaining experience.

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Ongoing Work & Future Plan
More sophisticated modelings and more validations
Game addictiveness may change over a game’s lifetime
Develop models that can explain WHY a game’s
lifetime is longer than another?
Due to particular game designs?
Due to commercial promotions or others?

41. Thank You!
Kuan-Ta Chen
Academia Sinica
http://www.iis.sinica.edu.tw/~swc