Visual analysis of single-case time series: Effects of variability, serial dependence, and magnitude of intervention effects

Visual analysis is the dominant method of analysis for single-case time series. The literature assumes that visual analysts will be conservative judges. We show that previous research into visual analysis has not adequately examined false alarm and miss rates or the effect of serial dependence. In order to measure false alarm and miss rates while varying serial dependence, amount of random variability, and effect size, 37 students undertaking a postgraduate course in single-case design and analysis were required to assess the presence of an intervention effect in each of 27 AB charts constructed using a first-order autoregressive model. Three levels of effect size and three levels of variability, representative of values found in published charts, were combined with autocorrelation coefficients of 0, 0.3 and 0.6 in a factorial design. False alarm rates were surprisingly high (16% to 84%). Positive autocorrelation and increased random variation both significantly increased the false alarm rates and interacted in a nonlinear fashion. Miss rates were relatively low (0% to 22%) and were not significantly affected by the design parameters. Thus, visual analysts were not conservative, and serial dependence did influence judgment.     

生活医学化与健康恐慌的关系及其反思*--论Michael Fitzpatrick《健康的暴政：医生及生活方式的控制》

迈克尔·菲茨帕特里克的《健康的暴政：医生及生活方式的控制》一书,以健康干预为主线,以健康政治化、生活医学化、疾病道德化为主题,论述了生活医学化的不同方面和形成过程,并力图揭示医学化背后隐含着的医学对社会的干预和控制。其中作者关于生活医学化和健康恐慌的一些哲学思考,尤其是生活医学化与健康恐慌的内涵及特点、生活医学化与健康恐慌的关系以及对生活医学化的审视与反思,在一定程度上蕴涵着对当今社会发展的启示。     

Situation awareness as a function of frame of reference, computer-graphics eyepoint elevation, and geometric field of view

The purpose of this study was to determine how 3 variables for the design of a "heads-down" spatial display--the frame of reference (pilot's eye vs. God's eye), geometric field of view, and elevation of the computer graphics eyepoint--influenced situation awareness. Thirteen flight-naive subjects each flew a simulated F-16 over a computer-generated flight environment to lock onto and intercept a series of sequentially appearing targets. The flight scene consisted of both an "out-the-window" view and a computer-generated heads-down spatial display showing an airplane symbol superimposed on a perspective view of the flight environment. During the interactive phase of the experiment, root mean square flight-path error, target lock-on time, and target acquisition time were measured. After the interactive phase of the study was completed, subjects were required to mark the location of the targets from memory on a computer-generated top-down view of the flight scene in an attempt to reconstruct the spatial mental model which subjects formed of the flight environment. The results for the interactive phase of the study indicated that performance was superior using the pilot's-eye display. However, for the spatial reconstruction task, performance was better using the God's-eye display. It was also shown that the ability to maintain the optimal flight-path using the more top-down view of the scene (600 eyepoint) was superior to the 300 eyepoint elevation. Implications of the results for the design of spatial instruments are discussed.