A pointing stick is an isometric joystick used as a pointing device, as with a touchpad or trackball, and typically mounted in a computer keyboard on a laptop or desktop computer. Movements of the pointing stick are echoed on the screen by movements of the pointer (or cursor) and other visual changes.
The pointing stick operates by sensing applied force, by using a pair of resistive strain gauges. The velocity of the pointer depends on the applied force. On a QWERTY keyboard, the stick is embedded between the "G", "H" and "B" keys, and the mouse buttons are placed just below the space bar. The mouse buttons can be operated right-handed or left-handed due to their placement below the keyboard along the centerline.
The pointing stick has a replaceable rubber cap, which can be a slightly rough "eraser head" material (Classic Dome) or other optional shapes (Soft Dome or Soft Rim). The cap is red on ThinkPads, but is also found in other colors on other machines, for example, gray or blue on some Dell models.
The user can often customize the operation of pointing sticks using software.
The user may be able to adjust the sensitivity of the pointing stick, so that application of a given amount of force moves the pointer a greater or smaller distance across the screen. The IBM TrackPoint III and the TrackPoint IV have a feature called Negative Inertia that causes the pointer's velocity to "overreact" when it is accelerated or decelerated. Negative Inertia is intended to avoid feeling of inertia or sluggishness when starting or stopping movement. Usability tests at IBM have shown that it is easier for users to position the pointer with Negative Inertia, and performance is 7.8% better.
The user may be able to specify "press-to-select", in which a sharp tap on the pointing stick is equivalent to a click of a specified mouse button.
A common problem of pointing sticks is the inability to identify the zero position (the position indicating no user touch). A typical solution, which reflects the fact that user operation of the pointing stick is rarely constant, is to interpret any absence of change of pressure (over a given interval, perhaps one or several seconds) as meaning the user has released the stick.
If the user applies exactly constant pressure to the stick for such an interval, this method mistakenly re-zeroes the stick. Then additional pressure is required to achieve the same movement of the screen cursor, and the cursor spontaneously moves in the opposite direction when the user releases the stick. If the user avoids touching the stick, the error ends when the stick detects the real zero position.
Separately, if "press-to-select" is enabled (see above), the user may generate inadvertent mouse clicks by touching the pointing stick during typing.
In 1984, Ted Selker, a researcher at PARC, worked on a pointing stick based on a study that a typist needs a relatively long 0.75 sec to shift the hand from the keyboard to the mouse, and comparable time to shift back. Selker built a model of a device that would minimize this time. It was only three years later, working at IBM, that Selker refined his design, resulting in the TrackPoint product on which IBM received US patents in 1996.
Comparison with touchpads 
Some users claim it is easier to finely position the pointer than when using a touchpad because there is virtually no "dead zone". Some users feel that pointing sticks cause less wrist strain, because user does not need to avoid resting wrists on a touchpad, usually located just below the keyboard. Some people find them more appealing for mobile gaming than a touchpad, because the track-point allows infinite movement without repositioning.
One criticism is that because the pointing stick depends on the user applying pressure, it can cause hand cramps (although this can be partly solved by setting the sensitivity to high, and lifting the finger when the pointer is not being moved). Another criticism is that it stresses the index finger and may lead to repetitive strain injury. In addition, a finger slipping off of the stick can lead to accidental pressing of one or more keys in immediate proximity.
A number of ergonomic studies to compare trackpoint and touchpad performance have been performed. Most studies find that touchpad is slightly faster; one study found that "the touchpad was operated 15% faster than the trackpoint." Another study found that average object selection time was faster with a touchpad, 1.7 sec compared to 2.2 sec with a trackpoint, and object manipulation took 6.2 sec with a touchpad, on average, against 8.1 sec with trackpoint.
Naming and brands 
|Name||Brand||Current Models||Past Models|
|TrackPoint||IBM / Lenovo||All known ThinkPads (not IdeaPads), and Travel Keyboard with Ultranav||Most ThinkPads, Space Saver II, Model M13, Model M4-1, Trackpoint IV, Trackpoint USB Keyboard, TransNote|
|PointStick||HP (Compaq)||All EliteBooks; ProBook 6450b, 6455b & 6550b||All EliteBooks; all models ending with p or w; all models starting with nc, nw or c; 6445b (optional), 6545b (optional), tc4200, tc4400; Presario models starting with v, 8500|
|NX Point||NEC||EasyNote MX45, MX65, S5|
|Pointing Stick||Sony||Sony Vaio Duo 11||Sony Vaio P series, BX series, C1 series, U8 series, UX series|
|Pointing Stick||Samsung||Serie 4, Serie 6|
|StickPoint, QuickPoint||Fujitsu||Lifebook T2020, P1630, P2120, S7220, E8420 (optional), U820/U2010||Lifebook T2010, S7110, S7210, B2400/2500/2600 series, E8310 (optional), E8410 (optional), P1100/1500/1600 series, U1010/U810/U50|
|Track Stick||Dell||Latitude E4310, E6410, E6420 and E6510; Precision M4700 and M6700||Latitude E6500, E6400, D430, D600, D630, D830, XT, E4300, E5400, E5410, E6400, E6510, E6400 ATG, E6500; Precision M2300, M2400, M4300, M4400, M4500, M4600, M6400, M6500; Inspiron 4000, 8100, 8200, 8600, 9100; L|
|AccuPoint||Toshiba||Tecra R840, R850, M11, A11 (optional)||Portégé (not current models 06/2007), 300-7000 series, T3000 series; Tecra series 500-9000, A7, A8, A9, A10, M2, M5, M9, M10, S Series; Satellite Pro series 400-4000, T2000; Satellite 100-4000 series, Libretto 50CT, 70CT, 100CT;|
|FlexPoint||Sprintek||SK8702/SK8703 for Laptop/Tablet PC/Netbook/Industrial Keyboard|
|FineTrack||Acer||TravelMate C200 (Tablet), C210 (Tablet), 6410, 6460, 6492, 6492G, 6592, 6592G, 6593|
|Mouse emulator||Elonex||Elonex ONE|
|Pointing Stick||Unicomp||EnduraPro, Mighty Mouse (both for desktops)||On-The-Stick|
Informal names 
In attempting to avoid trademarked names and the ambiguity of the term "pointing stick", which commonly refers to a stick used to point at chalkboards or flip charts, various informal names have been invented, including "cruiser", "nipple mouse", "nub", "eraser mouse", "wart", "joy button", "clit mouse", and "keyboard clit".
Other uses 
- "Lenovo Support and Downloads: TrackPoint Caps and how to order for ThinkPad systems and TrackPoint Keyboards". IBM.com. 2007-07-17. Retrieved 2009-04-06.
- US 5570111, Robert C. Barrett; Robert S. Olyha, Jr. & Joseph D. Rutledge, "Graphical user interface cursor positioning device having a negative inertia ...", issued 1996-10-29
- R. C. Barrett; E. J. Selker; J. D. Rutledge*; R. S. Olyha* (1995). Negative Inertia: A Dynamic Pointing Function. SIGCHI. Retrieved 2012-12-03.
- Golden, Peter. "The development of the IBM ThinkPad, Part I: big BLUE'S big ADVENTURE". Retrieved 2012-12-03.
- US 5521596, Edwin J. Selker & Joseph D. Rutledge, "Analog input device located in the primary typing area of a keyboard", issued 1996-05-28
- US 5489900, Matthew F. Cali; Jerome J. Cuomo & Donald J. Mikalsen et al., "Force sensitive transducer for use in a computer keyboard", issued 1996-02-06
- Miller, Paul (2009-01-07). "Sony VAIO P hands-on". Engadget. Retrieved 2012-12-03.
- Trackpoint vs Touchpad, discussion,By Jon Lee, April 25th 2007, jonlee.ca[dead link]
- Batra, S.; Dykstra, D.; Hsu, P.; Radle, K.; Wiedenbeck, S. (1998). "Pointing device performance for laptop computers". Proceedings of the Human Factors and Ergonomics Society 42nd Annual Meeting (Human Factors Society): 535–540.
- Sutter, C.; Ziefle, M (2005). Interacting with notebook input devices: An analysis of motor performance and users' expertise. Human Factors Society. pp. 169–187.
- Sutter, Christine; Armbrüster, Claudia; Oehl, Michael; Müsseler, Jochen (2008). Office work places with laptop computers: User specific requirements for input devices and software design (PDF). USA Publishing.
- Sutter, C.; Ziefle, M. (2003). "How to handle notebook input devices: an insight in button use strategy". Contemporary Ergonomics 2003 (Taylor & Francis Group). pp. 241–251. ISBN 9780415309943.
- Eric S. Raymond, Guy L. Steele Jr., et al. "nipple mouse". Jargon File. Retrieved 2011-07-08. Based on The New Hacker's Dictionary. MIT Press. 1996. ISBN 9780262680929.
- "TrackPoint Mouse". IBM. Retrieved 2012-12-03.
- IBM's TrackPoint page
- Pointing stick USB Keyboard Comparison
- Desktop keyboards with a pointing stick[dead link]
- How to configure the TrackPoint under Linux
- Notebook input devices put to the age test : the usability of trackpoint and touchpad for middle-aged adults Ergonomics, 2007, vol. 50, no3, pp. 426–445