The document discusses two case studies analyzing player motivation and behavior using behavioral economics and econometrics methods. Case 1 analyzes a social game called Play Garden and finds that a shutdown law increased both network effects and reverse network effects on social interaction. Case 2 analyzes an MMORPG called Ever Planet and finds that higher social distance (level difference between players) leads players to spend more time playing. Both cases used panel data analysis methods like 2SLS and fixed effects models to quantify motivation factors and measure their impact on player behavior.
2. Who we are
• Behavioral economics-based AI company
• Analyze games and user’s behavior and their motivation-
to-play
• Develop and service recommendation system based on
the user’s motivation-to-play
3. What I am going to talk about
• Introduce meta model for user’s motivation-to-play
• Introduce how to measure each motivation based on
player’s log data
• Introduce analysis cases
4. Meta model for motivation-to-play
SocialPersonal
Intrinsic
Personal
Satisfaction
Social
Interaction
Personal
Rewards
Public
Recognition
Extrinsic
• McGuinness M. 2015. Motivation for Creative People: How to Stay Creative While Gaining Money
• Rigby, S. and Skinner, T. GDC 2014, The Importance of Player Autonomy: Motivating Sustained Engagement through
Volition and Choice
• Baron J. GDC 1999, Glory and Shame: Powerful Psychology in Multiplayer Online Games
• Ryan, R.M. and Deci, E.L.2000. Intrinsic and Extrinsic Motivations: Classic Definitions and New Directions
5. Meta model for motivation-to-play
SocialPersonal
Intrinsic
Personal
Satisfaction
Social
Interaction
Personal
Rewards
Public
Recognition
Inherently interesting or
enjoyable
Extrinsic
• McGuinness M. 2015. Motivation for Creative People: How to Stay Creative While Gaining Money
• Rigby, S. and Skinner, T. GDC 2014, The Importance of Player Autonomy: Motivating Sustained Engagement through
Volition and Choice
• Baron J. GDC 1999, Glory and Shame: Powerful Psychology in Multiplayer Online Games
• Ryan, R.M. and Deci, E.L.2000. Intrinsic and Extrinsic Motivations: Classic Definitions and New Directions
6. Meta model for motivation-to-play
SocialPersonal
Intrinsic
Extrinsic
Personal
Satisfaction
Social
Interaction
Personal
Rewards
Public
Recognition
Inherently interesting or
enjoyable
Leads to a separable
outcome
• McGuinness M. 2015. Motivation for Creative People: How to Stay Creative While Gaining Money
• Rigby, S. and Skinner, T. GDC 2014, The Importance of Player Autonomy: Motivating Sustained Engagement through
Volition and Choice
• Baron J. GDC 1999, Glory and Shame: Powerful Psychology in Multiplayer Online Games
• Ryan, R.M. and Deci, E.L.2000. Intrinsic and Extrinsic Motivations: Classic Definitions and New Directions
7. Meta model for motivation-to-play
Intrinsic
Extrinsic
• McGuinness M. 2015. Motivation for Creative People: How to Stay Creative While Gaining Money
• Rigby, S. and Skinner, T. GDC 2014, The Importance of Player Autonomy: Motivating Sustained Engagement through
Volition and Choice
• Baron J. GDC 1999, Glory and Shame: Powerful Psychology in Multiplayer Online Games
• Ryan, R.M. and Deci, E.L.2000. Intrinsic and Extrinsic Motivations: Classic Definitions and New Directions
Personal
Satisfaction
Social
Interaction
Personal
Rewards
Public
Recognition
Inherently interesting or
enjoyable
Leads to a separable
outcome
SocialPersonal
Need for self expression
8. Meta model for motivation-to-play
Intrinsic
Extrinsic
• McGuinness M. 2015. Motivation for Creative People: How to Stay Creative While Gaining Money
• Rigby, S. and Skinner, T. GDC 2014, The Importance of Player Autonomy: Motivating Sustained Engagement through
Volition and Choice
• Baron J. GDC 1999, Glory and Shame: Powerful Psychology in Multiplayer Online Games
• Ryan, R.M. and Deci, E.L.2000. Intrinsic and Extrinsic Motivations: Classic Definitions and New Directions
Personal
Satisfaction
Social
Interaction
Personal
Rewards
Public
Recognition
Inherently interesting or
enjoyable
Leads to a separable
outcome
SocialPersonal
Need for self expression Other people’s opinions
matter
9. Who are social-intrinsic people?
SocialPersonal
Intrinsic
Extrinsic
• Harmony
• Collaboration
• Loyalty
• …
Personal
Satisfaction
Social
Interaction
Personal
Rewards
Public
Recognition
10. Who are social-extrinsic people?
Personal
Satisfaction
Social
Interaction
Personal
Rewards
Public
Recognition
SocialPersonal
Intrinsic
Extrinsic
• Recognition
• Appreciation
• Awards and Prizes
• …
11. Who are personal-extrinsic people?
Personal
Satisfaction
Social
Interaction
Personal
Rewards
Public
Recognition
SocialPersonal
Intrinsic
Extrinsic
• Money
• Privileges
• Opportunities
• …
12. Who are personal-intrinsic people?
Personal
Satisfaction
Social
Interaction
Personal
Rewards
Public
Recognition
SocialPersonal
Intrinsic
Extrinsic
• Pleasure
• Learning
• Meaning
• …
13. 3 Steps for implementing motivation model into games
RECOMMENDDEFINE FIND
(1) Define and parametrize the
motivation you want to find
Personal
Satisfaction
Social
Interaction
Personal
Rewards
Public
Recognition
14. 3 Steps for implementing motivation model into games
RECOMMENDDEFINE FIND
(2) Find each player’s motivation
based on the player’s log data
Install
Friend’s
introduction
The game is not what
player expected
Tutorial
Curiosity
No
interest
Quick
character
selection
Character
selection
Complex
game
Interest in
certain
characters
Induce
billing
Item
curiosity
Character
interest
No
interest
Fast level-
up
다른 캐릭터
경험
PvP
IAP
Set goals
Recommend item that
player is not interested
Login record
Usage of gold
record
Acquiring gold
record
Purchase record
Play info
Character choice
record
15. 3 Steps for implementing motivation model into games
RECOMMENDDEFINE FIND
(3) Send recommendation
message based on the
motivation
16. The result of automizing the three steps:
Retention rate
increased by 13%
User engagement
increased by 45%
In-app purchase
increased by 8%
Real case example:
Result of applying motivation-based recommendation system
in mobile game
17. Analysis methodology
How to define & parametrize & analyze the motivation model?
Behavioral Economics & Econometrics
• Behavioral economics: Study of the effect of psychological,
emotional, social factors on economic decisions of
individuals
• Econometrics: Statistical methods for empirical analysis
BUILD A MODELQUANTIFY PARAMETRIZE ANALYZE
18. Case 1: Play Garden
Social interaction in the social game (Play Garden)
Personal
Satisfaction
Social
Interaction
Personal
Rewards
Public
Recognition
19. Case 1: Play Garden
Social interaction in the social game (Play Garden)
Research Question: How shutdown law changed
the social interactions among players?
Shutdown law in South Korea
forbidding children under the age of
16 to play online video games
between 00:00~06:00
Personal
Satisfaction
Social
Interaction
Personal
Rewards
Public
Recognition
20. Case 1: Play Garden
Social interaction in the social game (Play Garden)
Social interaction Network effect
Find social interaction in Play Garden
As more users use a service,
they create more values, and
more people join
Personal
Satisfaction
Social
Interaction
Personal
Rewards
Public
Recognition
1
BUILD A MODELQUANTIFY PARAMETRIZE ANALYZE
21. Personal
Satisfaction
Social
Interaction
Personal
Rewards
Public
Recognition
Case 1: Play Garden
Social interaction in the social game (Play Garden)
More users ↔ the number of
concurrent users
Use a service & create more
value ↔ play time
Social interaction Network effect
As more users use a service,
they create more values, and
more people join
Find social interaction in Play Garden1
BUILD A MODELQUANTIFY PARAMETRIZE ANALYZE
22. Case 1: Play Garden
Social interaction in the social game (Play Garden)
Parametrize social interaction
The number of concurrent
users and their play time
Social interaction Network effect
Personal
Satisfaction
Social
Interaction
Personal
Rewards
Public
Recognition
• The number of concurrent
users
• Total play time for each
user for each day
• Other variables that may
affect the players:
• Level for each user on
specific day
• Gold each user has on
specific day
2
BUILD A MODELQUANTIFY PARAMETRIZE ANALYZE
23. Case 1: Play Garden
Social interaction in the social game (Play Garden)
Personal
Satisfaction
Social
Interaction
Personal
Rewards
Public
Recognition
The number of
concurrent users
The number of
concurrent users
The user’s play
time
- The user’s level
- Gold
- Weekend
- School vacations
- Demographics
Build a model measuring
social interaction and the
effect of shutdown policy
3
BUILD A MODELQUANTIFY PARAMETRIZE ANALYZE
Source: Kwon and Suh (2013)
24. Case 1: Play Garden
Social interaction in the social game (Play Garden)
Build a model measuring
social interaction and the
effect of shutdown policy
Personal
Satisfaction
Social
Interaction
Personal
Rewards
Public
Recognition
3
The number of
concurrent users
The number of
concurrent users
The user’s play
time
- The user’s level
- Gold
- Weekend
- School vacations
- Demographics
Shutdown Law
BUILD A MODELQUANTIFY PARAMETRIZE ANALYZE
Source: Kwon and Suh (2013)
25. Case 1: Play Garden
Social interaction in the social game (Play Garden)
BUILD A MODELQUANTIFY PARAMETRIZE ANALYZE
2SLS
A methodology for analyzing
the effect of independent
variables on the dependent
variable when there are
feedback loops in the model
Select the right methodology
and analyze
4
Chow Test
A methodology for testing
the presence of a structural
break at a specific event in
time series data
The number of
concurrent users
The number of
concurrent users
The user’s play
time
- The user’s level
- Gold
- Weekend
- School vacations
- Demographics
Shutdown Law
Source: Kwon and Suh (2013)
26. Case 1: Play Garden
Social interaction in the social game (Play Garden)
BUILD A MODELQUANTIFY PARAMETRIZE ANALYZE
Select the right methodology
and analyze
4
Personal
Satisfaction
Social
Interaction
Personal
Rewards
Public
Recognition
Source: Kwon and Suh (2013)
The number of
concurrent users
The number of
concurrent users
The user’s play
time
- The user’s level
- Gold
- Weekend
- School vacations
- Demographics
Result: Before shutdown law
No network effect
27. Case 1: Play Garden
Social interaction in the social game (Play Garden)
BUILD A MODELQUANTIFY PARAMETRIZE ANALYZE
Select the right methodology
and analyze
4
Personal
Satisfaction
Social
Interaction
Personal
Rewards
Public
Recognition
Source: Kwon and Suh (2013)
Result: After shutdown law
Network Effect & Reverse
Network Effect
The number of
concurrent users
The number of
concurrent users
The user’s play
time
- The user’s level
- Gold
- Weekend
- School vacations
- Demographics
Shutdown Law
28. Case 1: Play Garden
Social interaction in the social game (Play Garden)
BUILD A MODELQUANTIFY PARAMETRIZE ANALYZE
Select the right methodology
and analyze
4
Personal
Satisfaction
Social
Interaction
Personal
Rewards
Public
Recognition
Source: Kwon and Suh (2013)
Result: After shutdown law
Network Effect & Reverse
Network Effect
More concurrent
users
Play time
Fewer concurrent
users
29. Case 1: Play Garden
Social interaction in the social game (Play Garden)
BUILD A MODELQUANTIFY PARAMETRIZE ANALYZE
Select the right methodology
and analyze
4
Personal
Satisfaction
Social
Interaction
Personal
Rewards
Public
Recognition
Source: Kwon and Suh (2013)
Result: After shutdown law
Network Effect & Reverse
Network Effect
Play time
Reverse network
effect
More concurrent
users
Fewer concurrent
users
30. Case 1: Play Garden
Social interaction in the social game (Play Garden)
BUILD A MODELQUANTIFY PARAMETRIZE ANALYZE
Select the right methodology
and analyze
4
Personal
Satisfaction
Social
Interaction
Personal
Rewards
Public
Recognition
Source: Kwon and Suh (2013)
Result: After shutdown law
Network Effect & Reverse
Network Effect
Play time
Network effect
More concurrent
users
Fewer concurrent
users
31. Case 2: Ever Planet – Social distance
Public recognition in MMORPG (Ever Planet)
Personal
Satisfaction
Social
Interaction
Personal
Rewards
Public
Recognition
32. Case 2: Ever Planet – Social distance
Public recognition in MMORPG (Ever Planet)
Research Question: Does social distance influence
the player’s behavior in games?
Social distance is the gap
between different groups; social
class, race, gender, or sexuality.
In the virtual world, social distance
is the level difference between
existing users and new users.
Personal
Satisfaction
Social
Interaction
Personal
Rewards
Public
Recognition
33. Case 2: Ever Planet – Social distance
Public recognition in MMORPG (Ever Planet)
Public recognition Social distance
Find public recognition in Ever Planet
Personal
Satisfaction
Social
Interaction
Personal
Rewards
Public
Recognition
1
BUILD A MODELQUANTIFY PARAMETRIZE ANALYZE
The gap of levels among users;
mostly between existing users
and new users.
Source: Kim and Lee (2013)
34. Case 2: Ever Planet – Social distance
Public recognition in MMORPG (Ever Planet)
Parametrize public recognition
the difference between the user's level
and the average level of all users.
Public recognition Social distance
Personal
Satisfaction
Social
Interaction
Personal
Rewards
Public
Recognition
2
BUILD A MODELQUANTIFY PARAMETRIZE ANALYZE
• 𝑃𝑖𝑗: Total played time for
player j during day i
• 𝑆𝐷𝑖𝑗 = 𝐿𝑖,𝑗 − 𝐴𝑣𝑔(𝐿𝑖) Social
distance: difference between
player j’s level during day i and
average level of all users
during day i
• 𝐴𝑃𝑖𝑗 = 𝑘=1
𝑖−1
𝑃𝑖,𝑗: Accumulated
played time of player j from
day 1 to day i-1
• 𝑁𝑖: Number of players played
in day i
Source: Kim and Lee (2013)
35. Case 2: Ever Planet – Social distance
Public recognition in MMORPG (Ever Planet)
Personal
Satisfaction
Social
Interaction
Personal
Rewards
Public
Recognition
Build a model measuring public
recognition and its effect on the
player’s behavior
3
BUILD A MODELQUANTIFY PARAMETRIZE ANALYZE
Source: Kim and Lee (2013)
Social distance
The number of
concurrent users
The user’s play
time
- Accumulated
playtime
- Number of days
passed
- Weekend
- School vacations
36. Case 2: Ever Planet – Social distance
Public recognition in MMORPG (Ever Planet)
BUILD A MODELQUANTIFY PARAMETRIZE ANALYZE
Fixed effect
A methodology for analyzing
panel data when group
means are fixed for each
group.
Select the right methodology
and analyze
4
Source: Kim and Lee (2013)
Social distance
The number of
concurrent users
The user’s play
time
- Accumulated
playtime
- Number of days
passed
- Weekend
- School vacations
37. Case 2: Ever Planet – Social distance
Public recognition in MMORPG (Ever Planet)
BUILD A MODELQUANTIFY PARAMETRIZE ANALYZE
Select the right methodology
and analyze
4
Personal
Satisfaction
Social
Interaction
Personal
Rewards
Public
Recognition
Source: Kim and Lee (2013)
Result: As users have been playing more, they play
the less today
Social distance
The number of
concurrent users
The user’s play
time
- Accumulated
playtime
- Number of days
passed
- Weekend
- School vacations
(-)
38. Case 2: Ever Planet – Social distance
Public recognition in MMORPG (Ever Planet)
BUILD A MODELQUANTIFY PARAMETRIZE ANALYZE
Select the right methodology
and analyze
4
Personal
Satisfaction
Social
Interaction
Personal
Rewards
Public
Recognition
Source: Kim and Lee (2013)
Result: But the social distance makes people behave
differently; the higher level, the longer they play
Social distance
The number of
concurrent users
The user’s play
time
- Accumulated
playtime
- Number of days
passed
- Weekend
- School vacations
(+)
39. Case 2: Ever Planet – Social distance
Public recognition in MMORPG (Ever Planet)
Personal
Satisfaction
Social
Interaction
Personal
Rewards
Public
Recognition
Source: Kim and Lee (2013)
How to manage the social distance? Agent-Based Model
A computational model for
simulating the actions and
interactions of autonomous
agents
The simulation results show that when
the player-matching system is applied,
the game retention is significantly
increased.
The example of Divisions
and Tiers systems in
online / offline sports
Agent-Based Model simulation when the player-
matching system is applied in the game to reduce
social distance
Players
under Lv.50
Players
under Lv.30
No player-
matching
# of players
time
40. Case 2: Ever Planet – Game characteristics
Personal rewards in MMORPG (Ever Planet)
Research Question: How to categorize people
with personal rewards among various people?
In MMORPG, there are different
types of people, and we want to
distinguish people with different
kinds of motivations.
Personal
Satisfaction
Social
Interaction
Personal
Rewards
Public
Recognition
41. Case 2: Ever Planet – Game characteristics
Personal rewards in MMORPG (Ever Planet)
Find the characteristics of the game1
BUILD A MODELQUANTIFY PARAMETRIZE ANALYZE
Personal
Satisfaction
Social
Interaction
Personal
Rewards
Public
Recognition
Dungeons Playing parties
42. Case 2: Ever Planet – Game characteristics
Personal rewards in MMORPG (Ever Planet)
Dungeons Playing parties
Personal
Satisfaction
Social
Interaction
Personal
Rewards
Public
Recognition
Parametrize the characteristics of game2
BUILD A MODELQUANTIFY PARAMETRIZE ANALYZE
• 𝑃𝑇𝑖𝑗: Total played time for player
j on the day i
• 𝑃𝑇𝑖−1,𝑗: Total played time for
player j on the day i-1
• 𝐴𝑉𝐺_𝑃𝑆𝑖,𝑗: Average party size the
player j joined on the day i
• 𝑆𝑇𝐷_𝑃𝑆𝑖,𝑗: Standard deviation of
party size the player j joined on
the day i
• 𝐸𝑖,𝑗: The number of dungeons the
player j entered on the day i
Playing types; the number of dungeons entered
and the number of playing parties of each user
43. Case 2: Ever Planet – Game characteristics
Personal rewards in MMORPG (Ever Planet)
Build a model measuring the
characteristics of the game
3
BUILD A MODELQUANTIFY PARAMETRIZE ANALYZE
AVG_PartySize
The user’s play
time (t-1)
The user’s play
time (t)
- The number of
dungeon entries
- STD_PartySize
(how different
parties the user
joined)
Personal
Satisfaction
Social
Interaction
Personal
Rewards
Public
Recognition
44. Case 2: Ever Planet – Game characteristics
Personal rewards in MMORPG (Ever Planet)
BUILD A MODELQUANTIFY PARAMETRIZE ANALYZE
Random effect
A methodology for analyzing
panel data when there are
individual effects.
Select the right methodology
and analyze
4
AVG_PartySize
The user’s play
time (t-1)
The user’s play
time (t)
- The number of
dungeon entries
- STD_PartySize
(how different
parties the user
joined)
45. Case 2: Ever Planet – Game characteristics
Personal rewards in MMORPG (Ever Planet)
BUILD A MODELQUANTIFY PARAMETRIZE ANALYZE
Select the right methodology
and analyze
4Result: All variables in the model affect the user's
play time significantly.
AVG_PartySize
The user’s play
time (t-1)
The user’s play
time (t)
- The number of
dungeon entries
- STD_PartySize
(how different
parties the user
joined)
Personal
Satisfaction
Social
Interaction
Personal
Rewards
Public
Recognition
46. Case 2: Ever Planet – Game characteristics
Personal rewards in MMORPG (Ever Planet)
BUILD A MODELQUANTIFY PARAMETRIZE ANALYZE
Select the right methodology
and analyze
4Result: We can find the players with personal
rewards by removing the effect of party size and the
interaction effect of party size and the user's play
time.
AVG_PartySize
The user’s play
time (t-1)
The user’s play
time (t)
- The number of
dungeon entries
- STD_PartySize
(how different
parties the user
joined)
Personal
Satisfaction
Social
Interaction
Personal
Rewards
Public
Recognition
47. Case 3: Mobile Personal Health Record
Personal
Satisfaction
Social
Interaction
Personal
Rewards
Public
Recognition
Personal satisfaction in mPHR (My Chart in My Hand)
48. Case 3: Mobile Personal Health Record
Personal satisfaction in mPHR (My Chart in My Hand)
Research Question: Do people with personal
satisfaction have higher retention rates?
Health management function has a
self-monitoring feature, which
represents a personal intrinsic
personality.
Personal
Satisfaction
Social
Interaction
Personal
Rewards
Public
Recognition
49. Case 3: Mobile Personal Health Record
Personal satisfaction in mPHR (My Chart in My Hand)
Personal
satisfaction
Self-monitoring
Find personal satisfaction in mPHR1
BUILD A MODELQUANTIFY PARAMETRIZE ANALYZE
Tracking and updating the
user’s health information
Personal
Satisfaction
Social
Interaction
Personal
Rewards
Public
Recognition
50. Personal
Satisfaction
Social
Interaction
Personal
Rewards
Public
Recognition
Case 3: Mobile Personal Health Record
Personal satisfaction in mPHR (My Chart in My Hand)
Parametrize personal satisfaction
The average and the
frequency of usage
2
BUILD A MODELQUANTIFY PARAMETRIZE ANALYZE
Source: Lee et al. (2018)
Personal
satisfaction
Self-monitoring
• 𝐴𝑉𝐺_𝑆𝑀𝑖: Average usage of
self-monitoring function by
patient i
• 𝑆𝑇𝐷_𝑆𝑀𝑖: Standard deviation
of usage of self-monitoring
function by patient i
51. Case 3: Mobile Personal Health Record
Personal satisfaction in mPHR (My Chart in My Hand)
Build a model measuring each
feature’s effect on user retention
3
BUILD A MODELQUANTIFY PARAMETRIZE ANALYZE
Source: Lee et al. (2018)
Personal
Satisfaction
Social
Interaction
Personal
Rewards
Public
Recognition
The average usage of self-
monitoring function
The standard deviation of self-
monitoring function usage
User retention
- Demographics
- The level of
illness)
The average usage of other
functions
The standard deviation of other
function usages
52. Case 3: Mobile Personal Health Record
Personal satisfaction in mPHR (My Chart in My Hand)
BUILD A MODELQUANTIFY PARAMETRIZE ANALYZE
Cox proportional hazard
A methodology for analyzing
the expected time until an
event of interest happens
Select the right methodology
and analyze
4
Source: Lee et al. (2018)
The average usage of self-
monitoring function
The standard deviation of self-
monitoring function usage
User retention
- Demographics
- The level of
illness)
The average usage of other
functions
The standard deviation of other
function usages
53. Case 3: Mobile Personal Health Record
Personal satisfaction in mPHR (My Chart in My Hand)
BUILD A MODELQUANTIFY PARAMETRIZE ANALYZE
Select the right methodology
and analyze
4
Source: Lee et al. (2018)
Result: People with personal satisfaction have higher
retention rates.
Personal
Satisfaction
Social
Interaction
Personal
Rewards
Public
Recognition
The average usage of self-
monitoring function
The standard deviation of self-
monitoring function usage
User retention
- Demographics
- The level of
illness
The average usage of other
functions
The standard deviation of other
function usages
(+)
(-)
54. Wrap up
• Define and find the motivation of players in games
• Personal Satisfaction
• Social Interaction
• Personal Rewards
• Public Recognition
• Find the players with analysis methodology
• Recommend items and contents based on the motivation
55. Reference
• McGuinness M. 2015. Motivation for Creative People: How to Stay Creative While
Gaining Money
• Rigby, S. and Skinner, T. GDC 2014, The Importance of Player Autonomy:
Motivating Sustained Engagement through Volition and Choice
• Baron J. GDC 1999, Glory and Shame: Powerful Psychology in Multiplayer Online
Games
• Ryan, R.M. and Deci, E.L.2000. Intrinsic and Extrinsic Motivations: Classic
Definitions and New Directions, Contemporary Educational Psychology 25, 54–67
• Kwon, H., Suh, C. 2013, The Effect of the Shutdown System on Social Games,
Business Administration Research 6, 1-12
• Kim, M., Lee, B. 2013, Are There Too Many Superheroes? Analysis of the Social
Distance in Massive Multiplayer Online Role Playing Game,
https://ssrn.com/abstract=2330090
• Lee K, Kwon H, Lee B, Lee G, Lee JH, Park YR, et al. (2018) Effect of self-
monitoring on long-term patient engagement with mobile health applications. PLoS
ONE 13(7): e0201166. https:// doi.org/10.1371/journal.pone.0201166