Mobile Game Design: Stats, Skill and Luck

by Adam Telfer

All games feature three dimensions that determine player success: skill, stats and luck are required to win and progress in a game. However many prototypes and many games that I play each day seem to struggle with this mixture.

The main reason this happens is the player suffering from a lack of transparency  about how they can improve. If your players can’t answer the question: “Why did you lose this round?” — then you have issues in transparency.

You need to seek ways to isolate and clarify the impact of Skill, Stats and Luck to make your game engaging.

The Importance of Stats, Skill and Luck

To start to fix these issues of transparency, it is important to define what the balance of stats, skill and luck your game is. Each is important for the success of your game.

Stats are essentially everything that the player invests in outside of the core gameplay. Most games have RPG stat systems that players are seeking to upgrade. For example, upgrading building defense stats, upgrading unit abilities, or upgrading the speed of a car. These systems are most likely what paces and slows down the progression of the player. A strong stat system is necessary if you want to ensure a level 100 player feels dramatically more powerful than a level 1 player. These systems are most likely what your players are investing real dollars to purchase quickly and to give them an advantage in gameplay. Without stats, long term gameplay is extremely difficult — there’s nothing players can invest in to get better at your game.

Luck is any systems in your game that are purely random. For example, the gems falling down during Candy Crush or Hearthstone deciding which card will be drawn next from the deck. These systems are important to create drama and entropy in gameplay. Luck ensures that the gameplay never is boring since a positive (or negative) action can happen at any time. Luck also widens the breadth of skill needed to master the game. Being able to craft the best deck is easy, but being able to handle the near infinite possible outcomes of card order is an extremely difficult skill to master.

Skill is any player choices or player interactions that have an impact on the outcome of your game. Skill is the player’s ability to time jumps in Mario, their ability to effectively place units in Boom Beach, or their ability to choose between cards to play in Hearthstone. This variable is by far the most important to a player’s retention to your game. Players that feel the game has no skill will not stick to a game. Fun and engagement come from learning and feeling smart about one’s decisions (Theory of Fun, Raph Koster). Without skill, there is nothing to learn, there is no game.

Clash of Clans focuses on Stats and Skill. Stats comes from Units & Buildings. Skill comes from the player being able to choose location of attack.

For example, Clash of Clans clearly focuses on Stats and Skill. There are very few sources of luck in the game. Players seek to upgrade their buildings with currency to progress in the game. Stats is clearly the strongest focus for Clash of Clans to ensure that progressing and upgrades are felt and long-lasting. Skill is secondary: players optimize placement of buildings and placement of units to defend and attack. Skill is controlled and balanced very closely by Supercell.

Candy Crush focuses on Luck and Skill. There are no upgrades in Candy Crush, just boosts. These boosts can’t be upgraded, and give a very clear (transparent!) benefit to the player. Clearly Luck is their largest focus, ensuring that each move a player chooses they never will be able to predict fully what will happen. This creates casino-like “near misses” that are only cured through replaying a level or paying for boosts.

Different games on the top grossing chart focus on different balances of Stats, Skill and Luck. A rule of thumb is to select two of stats, skill and luck as your game’s focus.

The more factors that are included in your game, the more likely you will have issues with transparency. When the balance of Luck, Skill and Stats is unclear to the player, engagement suffers.

Be as Transparent as Possible

Fire Emblem Radiant Dawn. A Tactical RPG game. Control Movement of Units.

Let’s take for example a typical tactical RPG battle.
Each battle has a significant amount of variables that have an impact on its outcome:

  • Each unit has stats for attack, defense, speed, attack range, etc. (Stats)
  • A player can choose what unit types they want to bring into the battle. (Skill)
  • Each turn the player chooses where their units will move and when they will attack (Skill)
  • Each attack has a critical chance to do extra damage (Luck)

After a battle is concluded, the player lost. As a result, a player must ask themselves — what did I do wrong? How do I improve? What do I need to do in order to win this battle?

Fire Emblem. Stats, Skill and Luck go into the result of each battle.

It could be Stats: they need to upgrade their units more.
It could be Skill: they made poor decisions in the battle.
It could be Luck: they were just unlucky with critical hits.

Ensure your game is giving the player a clear answer.

When there are many variables determining your players’ success, it is best to isolate each variable as efficiently as possible.

When there are many variables determining your players’ success, it is best to isolate each variable as efficiently as possible. To isolate, you don’t always have to give feedback immediately when the action has occurred. Feedback on each variable can come before, during and after the gameplay.

Isolate Stats, Skill and Luck

Immediately from looking at the bar, I know that this is an “Extreme” race. To win, I need to upgrade.

CSR Racing is an excellent example of how games can isolate each variable. Before a race, CSR Racing isolates Skill from Stats. Using a small progress bar, they compare the player’s stat level against the opponent. If the race is going to be extremely difficult, the player is warned before they begin. This helps the game in two ways:

  1. Drives desire for Stats. Stats are given a clear value in the game. Players clearly see that if they improve their stats, they improve their chances of winning.
  2. Avoids unnecessary losses on levels that are too difficult. Many times players will blame their skill above all other factors. If they continually play a level that clearly isn’t balanced for their level, they will eventually feel the game is unnaturally difficult and leave.

CSR isolates Stats before the race with this small UI change.

Throughout the race the player gets clear feedback about their Skill.

CSR also seeks to isolate how much skill impacts the outcome of a race. During the race, the player gets very clear feedback about their timing skill. “Bad Shift”, “Good Shift” and “Perfect Shift” come up throughout the race giving immediate, clear feedback about how well the player is doing. At the end of the race, the player clearly can say “I had all perfect shifts! I did everything I could!”. Vice versa, a player can say “I had some bad shifts in there, maybe next time I can improve my time…”.

Through these two small mechanisms, CSR has effectively isolated skill from stats. Players clearly know the reason for winning and losing, and can decide the best course of action to improve their chances.

A Tool for Transparency

To start to fix issues of transparency it is imperative that you play test your game often. When discussing the game with playtesters be sure to ask after each core gameplay round :

“Why did you lose this battle?”
“What could you have done differently to win this [battle/race/round]?”
“How did you figure this out?”

If they can’t answer these questions, it is time to improve your transparency.

To improve, list the inputs (Variables) and outputs (Feedback) of your game:

  • Which variables impact the result? ex. Unit Stats, Unit Placement, etc.
  • How do we give feedback about each of these variables?
  • Which feedback systems are actually working? (players are acknowledging them in playtests)
  • Can we give strengthen feedback for this variable before, during or after the round?

Strengthening feedback is dependant on whether the variable is stats, skill or luck driven.

Pokemon is a good example of giving Skill-based feedback. Ensuring “Super-effective” comes up directly after the action make sure that players know that it was their skill that improved their outcome.

Variables that come from skill usually require more direct feedback immediately after the action is taken. For example, Pokemon gives the feedback “Super-Effective” immediately after a player has made a good choice about what attack to use against the opponent.

In Mario games, whenever mario is killed by a baddie, the game pauses and highlights exactly where mario was hit. This small and subtle trick ensures that players clearly see the reason for their failure and helps with learning.

Slots, Dice, Cards are all clearly luck based. Use them to ensure players know what is random and what is not.

Variables that are luck-based can be made more transparent by using expected visuals of where luck comes from. Use a deck of cards, a spinner, or a slot machine. These are expected to be pure random. Players will quickly understand that they have no skillful impact on these results.

Boom beach warns players when their opponent’s level is too high, and gives players the ability to “scout” before committing. Ensuring players can make the right choice about who to attack based on their Stat level.

Variables that are stats-based are easiest to give feedback before the round begins. Ensure you warn players before they are going into a battle without the necessary upgrades.

As you add strength to these feedback systems, continually play test your game. When players have a clear idea of how to improve their chances, your game will be far more engaging.


To increase engagement in your game, seek ways to make your systems more transparent in terms of skill-based, stat-based and luck-based variables.

Stats, Skill and Luck each have their own benefits and drawbacks to a game’s success. Ensure you know the focus and balance for your game. Balancing for high levels of all 3 is exceptionally difficult, and can only be accomplished through isolating Stats, Skill and Luck in a transparent way.

To ensure high engagement to a broad audience, be as transparent as possible why a player won or lost in your game. Listing out the variables leading to the outcome and analyzing whether the player has enough feedback is the first step to reducing confusion.

Your goal as a designer: Players should always know how to improve.