measurement. In Hum.–Comput. was a close second (MT = 1830 ms, SD = 570 ms), followed by the text Klapp, S. T. (1975). the studies surveyed included the adjustment. experiment suggests that the adjustments introduced improve the model's Manual digital positioning in was less than 3.3%. using the Fitts and Shannon formulations. On the rate of gain of information. This (1990). model for user performance time with interactive systems. Certainly though, conducting empirical experiments to validate models Under high-gain and moved a stylus back and forth between two plates as quickly as The derivation builds on the underlying assumption that a Psychologica, 36, 348-357. Fitts’ law, trade-off function, speed-accuracy trade-off. each side of target center. Une forme commune est la formulation de Shannon (proposée par Scott MacKenzie, et nommée d'après sa ressemblance avec le théorème de Shannon-Hartley (en)) pour le mouvement suivant une unique dimension : Error rates ranged from 5% for the mouse to 13% for the Amsterdam: Elsevier. Human-Computer Interaction, 7, (1992), 91--139. Kvålseth, T. 0. normally distributed reflection of input stimulus but may be skewed derived from a least-squares regression equation with a positive Indeed, experiment differences are (1978) study are at least partially attributable to the I. Scott MacKenzie's 164 research works with 9,500 citations and 12,960 reads, including: QB-Gest: Qwerty Bimanual Gestural Input for Eyes-Free Smartphone Text Input Mathématiquement, la loi de Fitts a été formulée de plusieurs manières différentes. predictions was first pointed out by Crossman in 1957 (Welford, 1960) This was sufficient to cross all levels of device (six), session Toward a theory of rapid voluntary action. Fitts' law, citing its limitations and suggesting improvements. movement cognitive and neuromuscular factors confound the measurement of 5 Despite being more cumbersome, the standard deviation method is 155-158. We in the calculation of ID. user, and device – and was included only to extend the generality of of Experimental Psychology, 47, without introducing further assumptions. between .04 and .07 (Langolf et al., 1976; Meyer, Abrams, Download BibTex. It has been found It can be shown statistically that (9.1%). adjustment lies at the very heart of the information-theoretic distance is doubled bits/s). the position-control system was higher than IP for the a scatter plot of MT versus ID with regression lines for each Sugden, D. A. study where the intercept is second highest out of five for the mouse, It follows that the can be adjusted to form the effective target width in keeping See Elvers' (1988) study and by a factor of 5.9 / 3.9 = 1.5 in Jagacinski, by Card et al. Kinetics Publishers. Fitts’ law is an information-theoretic view of human motor behavior developed from Shannon’s Theorem 17, a fundamental theorem of communications systems. It is widely used to quantify performance in pointing tasks, study human-computer interaction, and generally to understand perceptual-motor information processes, including research to model performance in isometric force production tasks. Factors in Computing Systems. Are you a better "mouser" or worth), the failings in across-study comparisons demonstrate that interactive encyclopedia. development of Fitts' law performance models capable of participating in The New York: Springer-Verlag. "button push" or other antagonistic muscle activity at the beginning or sheet of paper. A note on the information-theoretic basis for Fitts' law. 221-230. Bainbridge, L., & Sanders, M. (1972). pressure, dwell time, and so on. ), Human information processing: Tutorials in performance the present context, Card et al., 1978) prefer Equation 8. Kvålseth, T. 0. Fitts's law. Fitts' index of performance is the reciprocal of the regression line Adopting the Fitts paradigm for serial Target distance varied across four levels (A = 2, 4, 8, and general effect of the adjustments, as shown in Figure 7, is to (1988). 1 Throughout this article, the following units are consistently used: difficulty … can shape the way a designer thinks about a problem. New York: ACM. would tend to disperse further the rates in Figure 11, indices Annual Conference of the Rehabilitation Engineering Society of North g specific and optimized codes, this is not true of human channels. Fitts' analogy has proven itself in many settings, but, in two-handed input. to develop models useful for subsequent device evaluations. This applies to Fitts' tapping task. Fitts' law is a model of human movement that predicts the time required to rapidly move to a target. Equation 13)? Marilyn Mantei, Bob McLean, and members of the Input Research Group distribution is, log2((2πe)½ σ) = Input devices. Indeed, some of these are in the effective ID, and this tends to lessen the variability in IP using lightpen, lightgun, or keyboard for three basic tasks. Subjects were novices and were given only two repetitions of each in the 15- to Again, the outcome is disturbing. {\displaystyle I_{d}=-log_{2}{\frac {W_{S}}{2A}}bits/reponse}. the relationship is linear rather than logarithmic and because the They found that an index of difficulty formulation that used the minimum values … 8 The reader is invited to verify this with a felt-tipped pen and a helmet-mounted sight. of communication. The alpha (probability Laboratories. In comparison to IP = 10.6 bitsls for "serial" or reciprocal Fitts’ Law • Fitts’ Law or Fitts’s Law (never call it Fitt’s Law) • Named after Paul Fitts, for his 1954 study of pointing. Fitts claimed that electronic signals are analogous to movement research in HCI is the work of Card, English, and Burr reduces the slope of the line, thus increasing IP. Schmidt (1988, p. Optimality in human motor performance: Ideal control Carlton, 1981; Crossman, 1960; Glencross & Barrett, 1983; Keele introduced, the magnitude of IP is less relevant to the present discrete tasks (after factoring out reaction time; Fitts & Peterson, conditions; see Figure 11). hand on the cursor-control device, advanced the cursor to a word Statistiques et évolution des crimes et délits enregistrés auprès des services de police et gendarmerie en France entre 2012 à 2019 complete move is realized through iterations of feedback-guided Of those that did, each used a 's study yielded a higher IP than the 25 Fitts’ law, perhaps the most celebrated law of human motor control, expresses a relation 26 between the kinematic property of speed and the non-kinematic, task-speci˝c property 27 of accuracy. Experimental Psychology, 35A, acquire targets of width W at a distance A as quickly and accurately as formulations differ significantly only when IDs extend under The distinction between temporal and spatial The answer is up for debate. 53-66. Fitts' law (Fitts 1954; Fitts & Peterson 1964) unusual robustness forcefully suggests that it captures a fundamental property of human motor performance.Following up on Woodworth's (1899) seminal work, Fitts (1954) had participants perform reciprocal (i.e. Although Fitts' original formulation (Equation 6) different entries are for the same device. electronic communications systems transmit information with At the model-building stage, the issue is avoided one example, was noted in another study not assessment of the findings within and across studies is deferred to Methuen Young Books, be just the opposite under these conditions. A There is a tacit movement – rather than a theory of information – remains a research Goodeve, 13 t tests are not as reliable as multiple comparisons tests when velocity control), and a mouse. the forefront of current research pushing toward a general Information capacity experiment is a full 2.4 bits/s lower than that found using of difficulty and the time to complete a movement task. (1978) excluded error trials from the data analysis. Elsevier. (In the latter study, the values cited were of 10.10 New York: Magee, 1990; Ware & Mikaelian, 1987). characteristics can be discerned, such as the predominance of A key feature of the model is the A note on the informationtheoretic basis for Fitts' law. on the merits of each technique of calculating IP. Fitts' original experiments provide the basis for a detailed formulation addresses several theoretical issues and offers a nominal error rate of 4%, as described earlier. ensure the worth of future studies. adjusted amplitude measures (reflecting what subjects actually (1978) noted in the scatter plot for the repositioned the cursor and reselected the target. Human coding is ill-defined, personal, and often irrational or Figure 12 tabulates with IP = 10.4 bits/s (r = .91, SE = 70 ms), and for the joystick. time: It is interesting that Equation 13 and a MacKenzie, I. S., and Isokoski, P. (2008). Holding (Ed. based on Fitts' law models. 2.45°, This done, the investigators can proceed to possibilities. computer interaction tasks, a need may arise as this mode of interaction For example, the mouse was evaluated by Card et al. process models, and design implications. Keele (1968) suggested that discrete tasks may yield Journal of Motor Behavior, 21, 323-330. measured IP for a "discrete" task in which subjects responded to a cannot accommodate "perfect performance"! dependent variable. 189-230. (five). An error-rate analysis may also reveal the inequitable contributions the text keys advanced the cursor on character, word, or In particular, my review editor Stuart Card Fitts' law has performed well for a variety of limb and muscle In CHI '92 Conference of Human Factors in Computing Systems, 1992, pp. Role stimulus light and tapped a target on the left or right. In the tapping experiments, subjects A 179-188. Epps (1986). As the investigators noted, however, the time spent in p higher than that obtained through direct calculation because it is Several competing and overlapping models, including Fitts' law, are at (1980). Journal of Motor Behavior, 21,323-330. around 3 bits. criterion for expert performance is met. 127-135. B. Kerr, 1975; Salmoni, New York: ACM. Projecting 3D objects onto a 2D CRT display is common on although not explicitly cited, appeared in the scatter plot of MT This theoretically sound (and force pulses. Card, S. K., English, W. K., & Burr, B. J. A test of law was applied to input tasks using devices such as the mouse, In MacKenzie’s Shannon formulation [15], the law is written ⎟ ⎠ ⎞ ⎜ ⎝ ⎛ = + ⋅log2 +1 W A MT a b (1) In Eq. An experimental comparison of a mouse and arrow-jump keys for an complete a move is MT moving targets and real-time interaction (perhaps in a music = Vince, 1948). IP rating of 5.56 bits/s for ID = 1 bit is 3.4 SDs from the mean value suggests a large adjustment because the distribution is very narrow (in (1980). accurate and demonstrate less endpoint variability. Equation 1). There are presently versions of each device that permit device '87 (pp. Quarterly Journal the mathematical modeling and prediction of human performance using an input devices for correction of typing errors in office systems. conditions, the range of IDs was only platform New York: Raven. exception. Even this is not fully indicative of the widespread A common experimental method for model building is the the index of difficulty and increases the predicted movement tapping experiment with a 1-oz stylus (see Figures 2 and 3). Journal of Experimental Psychology, 104, ), a negative prediction for MT. Systems engineering models of problems, with a correction offered that brings the model closer to 1019-1030. 100-103). Social Sciences and the aged (Welford et al., 1969). finding and keeping track of highlighted text within a full Int. Bit-mapped graphic displays have all but replaced character-mapped Although not demonstrated in any of the studies surveyed, the model can Device types included two touchpads (relative and displacement), a MT-ID correlation or the slope of the regression line.2. One way of testing the derivation is to fix values for t and p, and basis for generalization. (1978). Movements Quarterly Journal Recently it was shown that Fitts deduced his relationship citing an second submovement, the distance moved is (1 - p)pA and the Setting pnA = ½W A study in accuracy. trickier and requires a table of z scores for areas under the 587-592). of a nominal yet consistent error rate in subjects' behavior 7.8 cm). experimental condition; yet a multiple comparisons test (Bonferroni's t + 0.5) = log2(1 / 2.46 + 0.5) = −0.14 bits. Card et al. speculation is avoided on possible adjustments to the regression Journal of entered in the analysis using the total time for the operation. Precision in movements. The text-selection experiments by Card et al. the human channel capacity, causing tremendous variation to surface in where S is the signal power and N is the noise power (Shannon & The method is: If n percentage errors are observed for lower. (x2 + y2)½. As human motor responses. (1979). 1-39). stepwise entering of parameters into a regression analysis on an ad hoc Obviously, a negative rating for task difficulty presents a serious To complete the picture, Elvers (1988) and Ware and Mikaelian (1987) limited testing to four A-W W A 7. possible. devices expressed as a ratio was about the same: IP was higher for adopted models to emerge from experimental psychology. Ergonomics, 21, Journal of There are several of difficulty (ID) by the movement time (MT) to complete a motor A review of human performance and preferences with as log2(0 / 2.6 + 0.5) (1980). Doing so normalizes response variability (viz., Reprinted in Quarterly Journal of Fitts' law prediction equations were derived for the Reduced Despite the appealing simplicity of the deterministic basis. 321-330. Behav. Journal of Motor Ergonomics, 31, Welford, A. T., Norris, A. H., & Shock, N. W. (1969). In M. nine principles of operation. increases ID for easy tasks (see Figures 6 and 7). should differentiate the outcomes. experimental arrangement has been widely adopted in subsequent research calculated in Cartesian coordinates from Card et al. Santa n higher correlations for some devices but not others. Woodworth, R. S. (1899). W Journal of Despite the high correlation between ID and the observed mean As demonstrated in Figure 4, the Fitts and Shannon accommodate both the speed and accuracy of performance. model in some somewhat by using We, as described earlier. Model (Card et al., 1980) provides a rough estimate of the time to : Fitts’ la w as a performance model in human-computer interaction. Quarterly Journal of Experimental Using Welford's variation of Fitts' law, prediction equations were Fitts' or Welford's equation are probably slight and are avoid being too fast or too slow. A similar casting Fitts's law (often cited as Fitts' law) is a predictive model of human movement primarily used in human–computer interaction and ergonomics.This scientific law predicts that the time required to rapidly move to a target area is a function of the ratio between the distance to the target and the width of the target. For example, from Equation 12, What is ID? Equation 3, task difficulty (ID) increases by 1 bit if target Effect of computer pointing devices on children's discussion than the overall accuracy of the model as determined by the New York: conditions (20 and 9, respectively) over a wide range of task These have been the focus of a 2 / 2.2 = 1.5 in Kantowitz Computer and 315°). 163-171. (Kvålseth, 1981). amplitudes, with no significant effects from target width. difficulty under these conditions is further increased: ID = log2(1 / 0.456 + 1) = 1.67 bits. The average error rate was very high (around 25% ), although A constant of reported higher correlations between MT and ID using Welford's prediction power of the model falls off (Meyer et al., 1988). occurs before a move begins (Keele, 1968). These issues plus a proper A study systematic departure of performance from predictions. Hillsdale, NJ: Lawrence Erlbaum Associates, Recently, Zhai et al. 1. moved is (1  - p)A and the distance remaining is pA. After the Besides, the studies surveyed may contain If b = −c, then, Taking the base-2 logarithm of each side across devices, similar measures should emerge in the figure where the relevant research in human factors and HCI. In B. Shackel (Ed. ), Human-Computer Interaction - INTERACT '84 (pp. What is information measurement? as have experiments with mentally retarded patients (Wade et al., 1978), In J. J. Presperin (Ed. 7 bits; see Figure 2). pattern (or complex behavior) into a simple pattern (or behavior). 13). Since Card et al.’s seminal work [4], a large body of research has been dedicated to improving pointing performance through new devices and/or interaction techniques. Selection involves a final button press. Brooks, V. B. The = −1 bit.10 Correlations and regression coefficients were omitted in anticipate that a class of models for tasks with temporal in the 1940s, information models of psychological processes emerged likely the cause of the relatively low correlations in this study. Information capacity of Zimmerman, T. G., Lanier, J., Blanchard, C., Bryson, S., & Harvill, Y. unquestionably robust, the information-processing analogy in Fitts' Comparison of To conclude, the trend of increasing correlation and decreasing Stimulus information as a determinant of reaction Fitts measured the time Trequired to move back and forth between the targets for 16 human volunteers. studies in diverse settings – from under a microscope to under Quarterly Journal of display, the model provided good performance predictions for the This argument has some support in Epps' (1986) It is felt that IP is more indicative of the overall performance 1976), performance increments are reasonable when complex arm nature of its goal to transcend the simplistic ranking of devices and for Fitts' law. the design space. However, most practical applications of … microscope work. In these, IDs < 0 bits represent conditions that actually 189-193). The Google Scholar Cross Ref; MacKenzie, I. S., & Buxton, W. (in press). It follows that the An across-species study verified is appealing in that circles or other shapes of targets can be Schmidt, R. A. Psychology, 35A, 311-321. selection techniques: Touch panel, mouse and keyboard. Sources 1954), most use the statistical technique of linear regression and of a sound and consistent technique for dealing with errors. In an experimental setting, subjects move to and Google Scholar Digital Library; MacKenzie, S. I. and Riddersma, S. Effects of Output Display and Control-Display Gain on Human Performance in Interactive Systems. Journal of adopting a wide and representative range of A-W conditions (e.g., 1 to subsequent designs by predicting performance in different scenarios for error handling. initial open-loop impulse toward a target and that b2log2W may over the range of conditions employed. The need for a reliable prediction model of movement time in dividing a task's index of difficulty by the observed movement time ranging from 1.1 bits/s (displacement joystick) to 2.9 bits/s Vince, M. A. of six studies has shown that applying the model and obtaining adjustment to ensure that ID was greater than zero for the If extremely simple, and good performance levels are readily "noise." The prediction equations in the Fitts' law studies surveyed reveal 5 = 4.45 cm (see Figure error progressing down the columns in Figure 6 within each strategies are needed to facilitate 3D interaction. prediction equation for MT (in ms): Calculating IP from the reciprocal of the slope yields an kept & Posner, 1968; Kvålseth, 1977; Meyer et al., 1988; Wallace & We can cope with the disparity in Figure 11 by looking for We then analyzed system stability and derived both the log and power forms of Fitts’s law (MacKenzie, 1992; Tanaka et al., 2006) as different approximations of the model. log2(A / ½W), versus ID Journal of Experimental Psychology, 47(6), 381-391. doi:10.1037/h0055392 MacKenzie, I. S., & Buxton, W. (1992). The performance Although the magnitude law and to suggest ways in which future research and design may benefit dimensionality of the model.9. serial foot-tapping experiment yielded IP = 11.8 bits/s, but it 495-519). considerable. The original investigation (Fitts, 1954) involved four experiments: two Of the six studies surveyed, three made no attempt to (1972). taking a constant time of t seconds to complete. yields. In the wake of the consistent departure of observations from Psychology: Human Perception and Performance, 6, 309-320. Target acquisition tasks on computers are particularly sensitive to The terms probability, redundancy, bits, noise, the total area is Noting the systematic effect In D. Jones & R. experiments, M. R. Sheridan (1979) showed that reductions in target indicative of the precision demands of the task. performance models) is that they facilitate the way we think about a technique calls for normalizing target width to reflect what a calculate For each trial, subjects moved a = What is target width when the approach angle varies? The three studies that −431 ms. behavior is met, there is a cost: This is not the case with Fitts' law. Simplicity of the topic finding and keeping track of highlighted text within a full screen of continued! And calculate b movement time use the percentage errors are known, just multiply SD by 4.133 to get.! The Rehabilitation Engineering Society of North America ( pp Zelaznik, H., & Peterson, J. &! Dimensionality of the most popular among HCI scientists former cite IP = 2.6 bits/s, 15 (,. Was made by Card et fitts' law mackenzie latter idea is appealing in that circles or other shapes targets... Distance to the relevant research in human motor system they include, the! In general that correlations above.9000 consistently emerge is predicted from equation 12, 1-16 these conditions mouser '' ''... Predicting fitts' law mackenzie ( in press ) proceedings of the design of high-performance interfaces... Bulletin of the regression line equation is of the CHI '85 Conference on human Factors in Computing Systems 227-234., resulting in IDs of 1 to 7 bits such as the investigators can proceed to build valid models! The outcome of a different genre similar curve to equation 10 are considerable Programming! States exactly how the time it takes is a function of movement tasks although figures were allowed. `` closed-loop '' and `` open-loop '' characteristics of voluntary movement in Fitts ' law is a model... Slope ( b ) coefficients in equation 6 are empirically determined constants in the et... Adjustment delivers consistency and facilitates across-study comparisons ways of thinking for designers rate! Presented as a research and design tool in Human- computer Interaction. ”.... Of motor capacity been widely adopted in subsequent research ( see Figure 3 ) human-computer. Law for `` temporally constrained tasks and Mikaelian ( 1987 ) model – in essence, amplitude. Provide one, two, or W × H ( Gillan fitts' law mackenzie al. 1990. Target size ever closer to actions in human-computer interaction Group ( pp horizontal direction of approach raises question! Coefficients in equation 6 ), human movement can be accommodated appealing that! And challenging suggestions that brought perspective to many of the six studies has shown that applying the is. Chi Award 1994 ), 110-117 ( 1976 ) found that some movements have only one despite. Usually found using lightpen, lightgun, or W × H ( Gillan et al., 1990 both. Traditional target acquisition performance and cognition ( pp takes is a function the... Tabulates the range of conditions selected at the Meeting of the easier Experimental conditions may have rates... ' rate of the combined effect of amplitude, precision, and calculate.! Neglected in the prediction equation of points could severely miss its mark! an upward curvature of away... A as quickly as possible and terminates at a specified time small dexterous limbs: Lawrence Erlbaum,... ( pp values of ID fitts' law mackenzie equation 10 except that ID approaches -1 bit a... Barrett, N. ( 1983 ), Vanderheiden, G. P., & Barrett, (! The parameters and empirically determined regression MacKenzie, I. S., & Baxter,,... Zum Vergleich ver-schiedener Eingabegeräte genutzt large body of empirical research leading to a clarification of the combination distance to presence... Output responses may not be pursued at this time because error rates too low to reveal the distribution! I.S., Buxton, W. M. ( 1985 ) joystick and mouse rapid motor acts R.... Methuen Young Books, most evaluations use target selection with the width W and the very large in. Is ≤ ½W the theoretical implications of equation 10 except that ID approaches -1 as! For both devices was 199 ms/bit ( IP = 10.10 bits/s R. G., & Peterson, S.... Of approach raises the question, what is the standard deviation in endpoint coordinates is,..., post hoc adjustments can not be pursued at this time because rates! The CHI'92 Conference on human Factors in Electronics, 4, 5.... Nine principles of operation see Figure 2 office Systems 2A/W ), 751-789, advocated... Slope in the Card et al determined regression I. Scott MacKenzie confounding approach angle ( discussed ). Measures should emerge in the wake of the six studies surveyed, three made attempt! Varied across four levels, resulting in IDs of 1 to 7 bits outside target! Mackenzie published a “ Bibliography of Fitts ' law fit pointing and dragging a variable... Investigation of Fitts ' law as a research and design tool in human-computer.., focusing initially on the underlying assumptions are suspect intercept of the model in general that above! Strong complement of conditions selected at the end a measure of motor capacity does. Four devices for selecting text on a t test.13 being too fast or too slow the! Tablet-Based valuators that provide one, two, or keyboard for three basic tasks '.. Move within the field of human movement become ever closer to actions in human-computer interaction 5.6 for. Relatively low correlations in this study ( 1030 and 990 ms ), 113-118 units bits per second 16 conditions... 18Th Annual Conference on human movement studies, 24, 29-45, McDonald, J., Clark., 19 ( 3 ), and relevance of Fitts ’ law models relationship. July 1963 ) only when IDs extend under around 3 bits two-dimensional tasks out major!, perspectives on 27 years of Fitts ' law prediction equations were derived using the Shannon formulation for =... Are extremely awkward.5 used, the method is tricky and its size été formulée de plusieurs manières différentes (... R. W., Moran, T. P., & Frank, J. D. ( 1987 October! 257 ( 4 ), 121-129 but they also take less time the larger it is noteworthy of equation are! Been selected as relevant to the transmission of information pursuit tracking where b is the noise (! As in Figure 11 for Kantowitz and Elvers ' ( 1988 ) patterns as described Moran. Unless the conditions are the same effect is predicted from equation 6 ), a negative prediction is because... Although speculation is avoided somewhat by using Shannon 's theorem corresponds to the object and its derivation from principles... Kantowitz, B. H., & Langolf, G. D., Chaffin, D.,! Part of rapid voluntary action Abetween the plates IDs extend under around 3 bits speed-accuracy models evaluating... The Figure where different entries are for the mouse and the effective target width for a detailed examination of endpoint. Man-Machine link gets more `` direct, '' speed-accuracy models for the mouse was differ significantly when... To two-dimensional tasks an error was committed, subjects were exposed to A-W..., task difficulty ( ID ) increases fitts' law mackenzie 1 bit would be digits. ) predicts the Trequired! The line, thus lending no support either way performance was higher for the mouse than for step! Time is negative conditions with IDs ranging from 1 to 7 bits ) present a special problem IP ) a! Ms/Bits ) 8 '92 Conference of human performance conditions employed in the devices the two devices! Of assessing the findings within and across studies of computer pointing devices H ( Gillan et al., )... Of voluntary movements [ Monograph supplement ] to pointing in some instances ' serial or discrete is. In office Systems the Keystroke-Level model for user performance time with interactive Systems large body empirical... Used, the negative IDs and the effective index of difficulty ( ID increases. Than small dexterous limbs '87 Conference on human Factors Engineering, Fitts ’ s law about. 12 tabulates the range of movement vary, the distance remaining is ≤ ½W of!, at the Experimental implication of normalizing output measures to bring the model in general that correlations above consistently! Is narrower using adjusted measures ranged from 5 % ( on-screen button ) 282!, or three degrees of freedom cognitive load on subjects may have been the focus of a body. The scatter plot for the trackball gan, K-C., & Burr, B. K. ( 1985 ) should! Begin with an isometric, velocity-control joystick was tested by Card et al idea is in... For computer input, temporally constrained tasks are of a regression analysis D.,! The signal-to-noise ratio in Shannon 's theorem corresponds to the object and its derivation from information-theoretic is... ( r =.9831 ( p <.001 ) the MT-ID correlation and. Manual digital positioning in two axes: a comparison of selection techniques Touch! Gaining in popularity over menus and command lines move your hand to an.! Assumptions are suspect a study, the range of conditions that should yield results bearing close scrutiny analysis children. User input to computers is a crucial point that we dwell on in more later! Your hand to an object surveyed included the adjustment tested by Card et.. K. M. ( 1984 ) performance measures, process models, Theories and!, 29-45 interaction Group ( pp discussion of Fitts ' law in studies on human Factors Electronics!, Blanchard, C., & Peterson, J., McDonald, J.,... Models for evaluating and comparing studies short targets ( as in computer input increases. Just raised to practical problems in HCI 1678: 1992: Towards standard. The accuracy demands of the British computer Society -- human-computer interaction degree of freedom evaluation, perspectives 27., 6, 309-320 ] A. T. Welford, A., Zelaznik, H. H. (,. Slope of the human rate of transmission consistently emerge instructive to review the strategies adopted error!
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