Fitts's Law - Model

Model

Fitts's law has been formulated mathematically in several different ways. One common form is the Shannon formulation (proposed by Scott MacKenzie, professor at York University, and named for its resemblance to the Shannon–Hartley theorem) for movement along a single dimension:

where:

  • T is the average time taken to complete the movement. (Traditionally, researchers have used the symbol MT for this, to mean movement time.)
  • a represents the start/stop time of the device (intercept) and
  • b stands for the inherent speed of the device (slope). These constants can be determined experimentally by fitting a straight line to measured data.
  • D is the distance from the starting point to the center of the target. (Traditionally, researchers have used the symbol A for this, to mean the amplitude of the movement.)
  • W is the width of the target measured along the axis of motion. W can also be thought of as the allowed error tolerance in the final position, since the final point of the motion must fall within ±W2 of the target's center.

From the equation, we see a speed–accuracy trade off associated with pointing, whereby targets that are smaller and/or further away require more time to acquire.

Read more about this topic:  Fitts's Law

Famous quotes containing the word model:

    When Titian was mixing brown madder,
    His model was posed up a ladder.
    Said Titian, “That position
    Calls for coition,”
    So he lept up the ladder and had her.
    Anonymous.

    Your home is regarded as a model home, your life as a model life. But all this splendor, and you along with it ... it’s just as though it were built upon a shifting quagmire. A moment may come, a word can be spoken, and both you and all this splendor will collapse.
    Henrik Ibsen (1828–1906)

    Research shows clearly that parents who have modeled nurturant, reassuring responses to infants’ fears and distress by soothing words and stroking gentleness have toddlers who already can stroke a crying child’s hair. Toddlers whose special adults model kindliness will even pick up a cookie dropped from a peer’s high chair and return it to the crying peer rather than eat it themselves!
    Alice Sterling Honig (20th century)