Positive-tempo

A positive tempo is where an individual has a one-step (or more) advantage in a battle and thus makes the first move, allowing them to set the pace and thus tempo. This can force opponents to be off-tempo, unable to keep up.

The opposite to a positive tempo is a negative one.

Usage
Positive tempo can be useful in it allows the individual to choose which strategy to utilise, and thus can allow them to choose a tactic that gives them an advantage and limits the option of the person in negative tempo.

However, by choosing the first move, it allows a negative tempo individual the possibility to predict the intended tactic and thus form counter-measures.

Examples
In chess, white would be considered positive-tempo because it makes the first move, and in tennis, the individual who is serving would be considered to have the positive tempo as they go first.