There are several components to the phenomenon that is thumbstick drift, but we can split them into two different categories: hardware and software.

The input of the thumbstick mechanism as stated earlier is displayed as both an X and Y axis. These two axis are mechanically controlled by two potentiometers, so by moving the thumbstick you allow electricity to flow across an axis for an input to be read by the controller. Popular testing
methods read these inputs on an (X,Y) graph, with values 0 to ±100 representing the percentage of input. At rest (0,0), there is no electricity moving across the axis, resulting in 0% movement in both the X and Y direction. And by moving the thumbstick a 5% difference-from-center left and up, we would read an input of (-5,+5).

As for software, we'll discuss the two common ways video games read and interpret these values when translating them to your characters movements in-game: Deadzone Settings and Response Types.

A controllers' thumbstick input is read on two different axis, the X-axis for left and right, and the Y-axis for up and down. Deadzone settings are the default values measured by the distance-from-center that a thumbstick can move before the game will begin to register your controller’s input. Once the input threshold has been crossed, the input is translated to in-game movement and your character begins moving. 'Controller Deadzone' can then be described simply as, "How far does the thumbstick move before you move in-game?".

A deadzone of 0.2 or 20% will mean the character will not move until the thumbstick is moved at least a 20% distance from the center of the axis, or rather (±20,0). Naturally, this can translate into a more sluggish feeling response with fast-paced gameplay as the thumbstick must be moved further before something happens on screen. Conversely, a lower deadzone setting of 0.05 or 5%, that can feel 'snappy' because of the shorter distance the thumbstick needs to travel before an input is registered. It is important to keep in mind that this setting's function is entirely dependent on the physical condition of the controller internals such as the potentiometers.

This setting is the multiplier the game uses applied to your thumbstick input that results in a specific movement or 'feeling' when aiming. Certain formulas are used to either accelerate or decelerate the input being sent from the thumbsticks, creating static movement patterns for players to become comfortable with.

Starting at the most straight forward, a Linear Response Type will register your controllers input at a 1:1 ratio, with a constant speed applied consistently to input percentage. More complex Response Types apply formulas to the receiving input to provide a smoother experience when moving the thumbstick, such as slowing the reticle for the first second to prevent overcorrecting, and quickening the speed of the reticle after to allow for faster movement to the desired position. This setting will vary from game to game as not all developers will use the same formulas, however it appears that a Linear Response Type is a raw baseline input reader that does not apply any software assistance or alteration to the controller input.

Combining these two settings together by lowering our Deadzones and utilizing a Linear Response, we can have a game instantly read a thumbstick input and prevent any alterations being made to the movement to simulate mouse-like precision on controller. Unfortunately, that result is also almost guaranteed to 'create' one of the most annoying issues out there for controller gamers - thumbstick drift.

The dreaded 'thumbstick drift' that plagues every controller user occurs when combination of all three components we discussed fall out of sync.

The component of the potentiometer that is most responsible for drift is a small ring of carbon that connects the electrical circuits of the thumbstick and allows inputs to be read. Over time and with use, the plastic parts that move (wipers) eventually wear down and shave enough carbon away to interfere with how well the potentiometer measures voltage. Once the carbon ring is too damaged to maintain a consistent connection, drift will start to occur. You may notice also after a long period of use, your thumbstick might have a little bit of wiggle to it, and is a result of other plastic components (saddle) being worn down as well.

Once a thumbstick mechanisms potentiometers have been worn out, which can happen due to a variety of reasons such as use over time or a 'rougher' playstyle, you will start to see jumps and inconsistencies in its values as the stick moves around. Where a thumbstick may have originally stayed (±4, ±3) at rest, may now read as (±8, ±4) at rest after heavy use. Taking into account certain deadzone settings and response types, a resting input of 0.08 or 8% will typically result in minor thumbstick drift across the screen.

Due to the circular input nature of thumbsticks and the variety of ways we play games, thumbstick components can deteriorate in all manners of ways, and no two controllers will develop drift at the same time or in the same manner because of this.

As Battle Beaver only modifies 1st Party controllers directly from Sony, Microsoft, and Nintendo, it's important to note that we are subject to the same manufacturing errors as any other customer of these big companies. Sometimes a controller will have bad values out of the box, and sometimes a controller can be a trusty companion for years before starting to drift.

The company that manufactures thumbstick mechanisms for the Big 'Three' has been doing so for a long time, and over the years, our own anecdotal evidence, we have seen a decline in the durability of the components used in mechanism construction. So while there is something to be said about wanting the most out of your controller, it is important to note that across the board we have seen a trend of controllers beginning to drift sooner and sooner.