Mechanics-Dynamics-Aesthetics (MDA) is a design framework that helps video game designers (and the software developers who work with them) understand what effect a game's rules, player capabilities and setting have on the success of a game. The framework was developed as part of a game design and tuning workshop held in in San Jose, California around the turn of the century.
The MDA framework supports the idea that from a developer's point of view, successful games are a collection of loosely-couple discrete outputs. The framework encourages developers and designers to correlate design elements with software deliverables. The framework supports a formal, iterative approach to design and tuning in which each component of the MDA framework provides a unique view of the game's design.
Mechanics refers to the ways in which the game's programming code affects the game. Mechanics themselves are generally not observable, but their effect can be felt and observed through interactions. Dynamics are the observable results engendered by the game's mechanics. Aesthetics refers not only to the visual appearance of a game, but also to the player’s emotional responses when playing the game.
If a designer is tuning the mechanics of the game, for example, he or she might analyze the game's software artifacts. If the designer is tuning dynamics, on the other hand, he or she might look at user input options. If the designer is tuning aesthetics, he or she might focus ways to encourage the player to play for longer periods of time.