Stat Grinding

Ever since the first Role-playing games like Dungeons and Dragons, most RPGs have used the system of simply leveling up once you have hit enough Experience Points. But that doesn't mean that some companies haven't tried to make an alternative to simple leveling to try something a bit different.

One of the most common is Stat based grinding. In an RPG that uses this system, there are no actual "Levels" to gain, per se. Instead, you are playing to increase your stats. As opposed to leveling up the character overall and giving them a boost to every stat, you level up each stat individually, or can work on multiple ones. How do you do this? It's actually rather simple, use the stat more and then you gain it. So you would gain more strength and accuracy by landing successful damaging hits on enemies, and vice versa for other stats.

This is based off of real life workouts. If you want to boost your overall strength, you practice lifting more and more weight, but if you want to boost endurance, then you practice bigger reps. One of the pros of Stat based grinding is that you can customize characters a little more this way, and it can give that feel of immersion to it. (Such as say, Morrowind.) It also gives some strategizing because you need a certain stat but you don't just go out smacking enemies to level up your magic stat.

But as appealing as the system sounds in theory, in practice there are many pitfalls which can make it... not so good. If not balanced correctly, Stat Grinding can take considerably longer than Level Grinding. One common cause is the Catch-22 inherent in the system: If you are lacking in a given stat, the only way to train it is to perform an action dependent on the stat; most attempts to perform said action will fail, because your stat is too low, and so you don't get any experience for doing it. If your attacks never connect, you have to train your Dexterity, but your attacks never connect, so you can't train that stat. Games with Level Grinding let you grow your skills by training unrelated ones; in Stat Grinding games, no such luck.

Additionally, how efficiently you are able to train your stats depends not only on the your actions in battle, but the enemies' actions as well. If there is no way to manipulate enemies into doing certain things (taunting enemies to make them attack you, blinding enemies so that they must use magic, etc.), then your character's growth is entirely dependent on the Artificial Intelligence of your opponents. If AI Roulette is in full force, your only recourse is to pray to the Random Number God.

Another minor drawback may be that with the absence of levels, it can be a little harder to gauge how strong you should be by a certain point. Levels give you an idea on what level you should be before attempting a certain sidequest or starting off an event. But if the enemies scale with you, this wouldn't be a problem.

In practice, it often falls into a Violation of Common Sense. The enemies may not always attack who you want them to, so a good way to level up your characters' health and defense? Intentionally place them in harm's way, and let enemies beat on them.

Other games do actually combine simple Level Grinding with Stat based grinding. Since statistics and percentages are the bread and butter of the RPG Genre (don't let those fanboys prove you wrong) and it is your statistics that rule the battlefield, you may not start off automatically knowing how to use an axe as effectively as a sword. Some games instead make you train an individual skill in a weapon or armour proficiency by using it, or commonly, trade skills. These may often not require grinding, or at least as much as stat-grinding. (Commonly, MMORPGs have this type of grinding with professions.)

Action Adventure

 * Brave Fencer Musashi also had this, but it also combined an item-based leveling up system with stat-based grinding. While Musashi's swords and defense increased the more he fought, his health wouldn't. He had to be given an item that would increase his max HP.
 * Quest for Glory requires you to perform one action repeatedly in order to build it up.

MMORPGs

 * The Mabinogi skill system is drenched with this. Every single skill level comes with a list of successes, failures, particular results and specific applications that must be met to level the skill up, plus requiring a bunch of AP. It works well for the most part, but you can run into difficulty when it comes to higher-level craft skills that require a certain amount of successes and failures to level. If you level the craft skill too high too quickly, then it becomes harder to accumulate the necessary number of failures than the number of successes.
 * Runescape pretty much uses a combination of this and Level Grinding. Each skill such as health, defense, strength, prayer, cooking, etc all had skill levels, and you don't exactly gain a single level to raise the combat level, per se, you increase your Strength, attack, and defense. Certain actions give the player with experience towards a specific skill level.
 * Tibia uses this for every weapon, shield, fishing and magic strength. You are only able to learn magic at a certain level though. The catch is that each class has certain skills raised quicker than others.
 * RF Online has this as its entire basis. You still gain levels, yes, but these are mainly used to limit the maximum HP and the level of every stat & spell available. Want to use those high level spells? Then you'll have to not only increase your Force level, but your White/Dark Force level too. Its so prevalent that its not uncommon to see a player getting mobbed by 30 monsters just to level his Shield stat.
 * World of Warcraft uses the variety for trade skills: basically, doing an orange combine, harvest, or what have you is guaranteed to give at least one skillup, yellow is highly likely, green is unlikely, and gray won't.
 * An older version of Fly FF does this with skill grinding, ie. you gain experience for a certain spell everytime you cast it and after a certain amount of experience in it, it levels up. However, this was replaced with the usual skill point system like in most other MMO's after a big update patch.

Roguelike

 * Dwarf Fortress uses this. In Adventure mode, this is what you'd expect. In Fortress mode, not so much.

Role Playing Game

 * One of the first games to do this was Final Fantasy II. Many things are still done today, but one of the things people made fun of in Final Fantasy II was that the most efficient way to power up your characters wasn't to kill enemies. It was to order your characters to smack themselves across the head with their weapons. Seriously. The way it was set up, you were helping yourself more when targeting yourselves and attacking than you were beating up the enemies as you were intended. It was also the most surefire way to level up the Cure magic. Even in the remakes, this remains one of the best ways to gain experience and empower your characters.
 * Magic was also a different story entirely, and was almost as big of a Catch22 as evasion stats. You had to cast spells and after a specific time, they'd level up. This unfortunately meant that while magic can be powerful after all, it's just too tedious to level up since your characters can become just as powerful after a few rounds of masochism than they would fighting a million battles with magic. It also didn't help that you could still inflict dinky damage with the most powerful spell in the game's world because your intellect stat was still low.
 * The NES version was considered a little easier for magic-fans because there was actually a benevolent glitch that enabled you to simply select and deselect the spell over and over again and it eventually levels up.
 * The remake made it so that magic levels faster than weapons. (Though still not as easy to powerlevel as exploiting a glitch.) The Bonus Dungeon is much less tedious if you go at it with a party of mages.
 * Final Fantasy II also had another method to keep you from maxing all your characters stats out so even the manly-fighter Gus wouldn't wind up also being a formidable magic user: Whenever you worked on some stats, others would actually go down. This was removed in the remakes, meaning one could just make ridiculously powerful and nearly identical characters with enough time.
 * Final Fantasy X's Sphere Grid. Leveling up does not raise stats; it just grants you moves on the Sphere Grid. To boost your stats, you use spheres to activate spaces on the grid that boost your characters' stats and grant them new abilities.
 * Final Fantasy XIIIs Crystarium is very similar to Final Fantasy Xs Sphere Grid, except the "grids" were unique to each character, not universal, and the ability/stat unlocks just required enough points.
 * SaGa used this a lot, and was one of the Trope Codifiers, although the method of grinding changed depending on the game:
 * Makai Toushi SaGa (aka Final Fantasy Legend) primarily did this with mutants. Humans could use items to speed the process, and monsters simply evolved into stronger monsters with fixed stat values (a hidden "rank" stat on monsters and enemies allowed for some real shenanigans, such as evolving a monster to one of the monsters outside of the last boss's room... before ever entering the tower).
 * SaGa 2 (aka Final Fantasy Legend 2) also did this, but humans could gain stats the same way Mutants did too. Monsters evolved the same way with the fixed-stat-values (and the inability to use weapons). But there was another class that leveled up a different way... robots. Robots would simply have their stats increased by equipment that is given to them, with the theory that it's added on as an upgrade.
 * There are also some potential Catch 22 situations, and when dealing with parties of robots and monsters mixed with humans and mutants, monsters and robots may be ordered to defend or do something useless so humans and mutants could be able to take the appropriate action to gain stats.
 * Romancing SaGa 1-3 tended towards everyone using the Human type stat gain method from SaGa 2, although they gained random special attacks and spells based on the attack types they would use.
 * Saga Frontier brought back Robots and Monsters to the mix, adding an additional twist—Robots could switch bodies outright, gaining intrinsic stats and abilities on top of their equipment.
 * Used in Elder Scrolls. Also helps when it's a solo game and your character is pretty much a Game Breaker by the end anyhow, and it uses Level Scaling. Many skills are leveled up this way.
 * Quite frustrating in Morrowind was that you only made progress to leveling a skill on a successful use. Evidently people in Tamriel don't learn from their failures. Unless you want to spend half an hour swinging and missing a broadsword at a worm at your feet, nearly every non-Primary/Secondary skill on your character sheet required a small fortune in training before it would successfully go off once. I feel I should mention Crack is Cheaper, because skooma actually is.
 * Also consider grinding spellcasting as a non-spellcaster. Your basic fireball has a laughable chance of success, costs a good chunk of your mana bar (whether it works or not), and the bar doesn't recharge until you rest. Plug-ins aside, there are two ways to grind:
 * Buy an already cheap and weak spell of the school you need. Craft the weakest spell possible with that effect, e.g. "heal 1" or "chameleon 1 for 1 sec". Cast until out of mana, sleep, repeat. Proceed until school of magic skilled enough to actually use. Works with all spells, just be careful to practice anything offensive indoors and if possible, after dispatching the inhabitants.
 * As a case of heavy meta-gaming or a possible exploit, maybe a developer oversight, there is a single NPC selling the "Drain Skill" spell. Craft "Drain Skill ??? for 100 points for 1 sec on yourself" and get to the trainer. Drain, train for some measly coins (training any skill 1 to 2 is dirt cheap), watch skill rise by 1 - the drain skill correctly restores as many points as drained. Repeat until satisfaction.
 * Maybe it was a good thing the alchemy was obscenely buggy and exploitable. To elaborate: While the game engine of Morrowind didn't allow for more than one dose of a particular potion to be effective at the same time, crafted potions worked slightly differently. The same potion made twice, with the same ingredients, didn't count as the same potion mechanically so long as it granted even slightly different bonuses. Since Alchemy was Intelligence-based, it was simply a matter of producing an Intelligence-boosting potion, drinking it, gaining the buff and repeating until you eventually produced potions with effect values in the millions and durations of in-game decades. As the whole process is exponential, this actually happened fairly quickly.
 * Oblivion made this far less painful, as failed attempts at crafting counted toward skilling up, accuracy rolls in combat were removed altogether, and your mana bar recharged passively. However, the skill points and attributes in Oblivion are handled in such a way that efficient grinding requires a lot of micromanagement. The limits on training also make this a pain.
 * The Total Conversion Nehrim features this technically, but every skill is considered minor and raises REALLY slow. Instead, you mainly rely on Experience Points and leveling up, which grants you skill points that can be spent at trainers, ala Gothic
 * Skyrim also has failed attempts get you experience as well.
 * Special Abilities use this system in Soul Nomad and The World Eaters.
 * The first Digimon World had no levels. You raise your Digimon's stats by having them train at the gym, by feeding them chips, or by having them win battles. (Unfortunately it was a grind for levels.)
 * The fact that your Digimon partner has a limited lifespan before needing to be recycled from scratch as a Baby level doesn't help, either.
 * In The World Ends With You, your stats do not increase except by eating food. Leveling up only affects your health. Pins also develop this way.
 * Secret of Mana had skills for each weapon and element, which increased with use and raised the damage/healing/duration/whatever of the skill you were using. The weapon skills also let you charge up a special attack.
 * Its Spiritual Successor, Secret of Evermore, also had this system, but with much lower level caps for weapons. Alchemy spells could be raised to level 9, and could be cast in quick succession for easy leveling (provided you had enough reagents to use them).
 * Disgaea games have two forms of this.
 * The item world makes items stronger as you pass through the dungeons within.
 * Using weapons and skills increases their power for any character.
 * Pokémon has the Species and Level System, randomly-determined stats, and this in effect all at once. The first of these determines the bulk of your stats, modified by the second system, called Individual Value (IV) or PokeDNA—a sliding score of 0 to 31 that determines an individual Pokemon's modified potential in any given stat. The third is called EV—Effort Value, and plays this trope straight—the Pokemon gains 1-3 points to 1-3 of their 6 stats based on what type of Pokemon they defeat. Vitamins can also give set amounts of EV, up to about half the total cap, and certain berries remove set amounts. Changes to EV typically only register at level-up, but putting the pokemon into storage also recalculates it's stats. The original game had caps on each stat, but no overall cap; every game since the first has a set cap of 255 effort points in any given stat and 510 total.
 * In Fable, using an ability of one of the three types (Strength, Skill and Will) gives you a form of XP that you can use alongside regular XP to level up abilities of that type.
 * Quest 64 used this in a way that ignored typical level up systems. Of course, it still required work, but it was better than relying on a bad level up.
 * Vagrant Story twists this trope by applying it not to its protagonist, but to his equipment: the more a weapon is used to kill a certain type of enemy (Human, Undead, Demon, etc.), the stronger it becomes against that type, while simultaneously becoming weaker against the others. This means that any one weapon could only be truly effective against two types at best, forcing the player to carry several differently "trained" weapons at all times, switching between them as the situation demands. Also, the only way to effectively grind some of the rarer enemy types was to find their Training Dummy and wail on it... for tens of minutes at a time. Between these two facts, this implementation ended up driving away a lot of players.
 * Some of the Grandia games up weapons and spells by using them.

Simulation Game

 * Rune Factory has this. Farming, taming, melee, magic, cooking, weapon crafting, clothes making...there's a stat for everything.
 * Rune Factory 3 takes it to hilarious extremes. You can level up eating, walking, and sleeping.

Tabletop Games

 * The World of Darkness has a variation of this, where you choose which stats to boost to use your experience.
 * Chaosium's Basic Role Playing system did this first with Rune Quest, and later in Call of Cthulhu (tabletop game), Elric!/Stormbringer, Superworld and others. It took a successful roll to become eligible for a chance at improvement, and then between sessions (one week) the roll was made to increase the skill. There was also the possibility of taking formal training for skills and characteristics, but in Superworld (a generic superhero RPG), a critical success, special success, or fumble with a characteristic allowed to improve the characteristic as well.
 * Bunnies and Burrows used this system, where every time a character used a statistic, they would roll at the end of the play session to try and increase their level (not their ability) in that statistic.
 * PDQ# inverts the trope; you have to fail a roll to get Training Points (the logic being that, if you succeed, the challenge was too easy for you to learn anything from it).

Turn-Based Strategy

 * Partially done in Disgaea, which has regular level-ups, but also has a system by which spells become more powerful/cover more range the more you use them, and you become more proficient with a given weapon the more you use that.
 * Phantom Brave combines both Level Grinding and Stat Grinding for both your characters and the items they can wield.
 * In the X-COM titles, this is how your soldiers become better over time. Several statistics (Time Units, Strength, etc.) gain experience for any successful action, while more active stats like Firing/Throwing Accuracy are trained by hitting aliens.
 * The Fire Emblem games use this for weapon proficiency gains, in that by attacking with a certain weapon/magic (or healing with staves) enough times will allow the character to use the next relevant level of arms.

Web Comics

 * In El Goonish Shive, Nanase takes this approach to trying to learn more spells once she realizes she can.