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Regression analyses are increasingly being used to provide confirmatory evidence for models of human performance. The amount of information made available to judge these models is reduced because clearly established standards in the techniques of performing and reporting regression analyses are lacking. This paper addresses two primary problems in regression analysis: aggregation of data and the aggregation of variables into composite models. We provide examples of the misuse of regression techniques and recommend ways in which the amount of information made available to evaluate the model being tested can be maximized in analysis and reporting.

System responsiveness (SR) is defined as the elapsed time until a system responds to user control. SR fluctuates over time, so it must be described statistically with mean (MSR) and standard deviation (SDSR). In this paper, we examine SR in virtual environments (VEs), outlining its components and methods of experimental measurement and manipulation. Three studies of MSR and SDSR effects on performance of grasp and placement tasks are then presented. The studies used within-subjects designs with 11, 12, and 10 participants, respectively. Results showed that SDSR affected performance only if it was above 82 ms. Placement required more frequent visual feedback and was more sensitive to SR. We infer that VE designers need not tightly control SDSR and may wish to vary SR control based on required visual feedback frequency. These results may be used to improve the human-computer interface in a wide range of interactive graphical applications, including scientific visualization, training, mental health, and entertainment.

This research examines how people make movements with pointing devices during human-computer interaction. It specifically concerns the perceptual-motor processes that mediate the speed and accuracy of cursor positioning with electromechanical mice. In three experiments we investigated the spatial and temporal characteristics of positioning movements made with a mouse, analyzing subjects' speed and accuracy as a function of the types of targets that the movements had to reach. Experiment 1 required rapid and accurate horizontal movements to targets that were vertical ribbons located at various distances from the mouse's starting location. The targets for Experiments 2 and 3, respectively, were vertical lines having various heights and rectangular boxes having various heights and widths. Constraints on movement distance along the primary (that is, horizontal) line of motion had the greatest effects on total positioning times. However, constraints on movement distance along a secondary (vertical) line of motion also affected total positioning times significantly. These effects may be localized in different phases of movement (e.g., movement execution and verification). The duration of movement execution (i.e., physical motion) depends primarily on the target distance, whereas the duration of movement verification (i.e., check for endpoint accuracy) depends primarily on target height and width. A useful account of movement execution is provided by stochastic optimized-sub movement models, which have significant implications for designing mice and menu-driven displays.

We assessed constraints on daily living of 59 healthy, active adults 65–88 years of age in focus group interviews. Individual comments about specific problems were coded along the dimensions of (a) the locus of the problem (motor, visual, auditory, cognitive, external, or health limitations); (b) the activity involved (e.g., transportation, leisure, housekeeping); (c) whether the problem was attributable to task difficulty or the perception of risk; and (d) response to limitations (perseverance, cessation, compensation, or self-improvement). The data provide information about the types of difficulties encountered in everyday activities as well as the way in which individuals respond to such difficulties. Each comment was also coded in terms of whether it was remediable via training, design changes, or some combination of the two. More than half of the problems that were reported had the potential to be improved in some way, thus providing direction for future research in human factors and aging. Actual or potential applications of this research include identifying problems and difficulties that older adults encounter in daily activities such as transportation and leisure; more specifically, determining the degree to which such problems are potentially remediable by human factors solutions. Applications of this research also include understanding the types of systems, products, and technologies that older adults interact with currently, or are interested in learning to use.

We examined age-related effects on decision making in a task environment familiar to most younger and older adults. Participants made route-selection decisions in real time. Participants received information about traffic density and expected speed limits of main and alternative routes, from which they determined the optimality of their present route versus alternative routes. The experiment evaluated the effects of information type, amount of congestion, alternative route speed limit, and age on speed and quality of decision making. Measures of optimal route selection revealed main effects of alternative route speed limit, congestion level, and message type, but there was not a main effect of age, and age did not interact with any variable. In terms of decision speed (but not quality of decision making), older participants were slower, and age interacted with alternative route speed and with message type. The data are interpreted in relation to previous data examining everyday problem solving and aging.

The present study assessed the success of several instructional programs in teaching the use of automatic teller machines (ATMs). Fifty-six older adults (aged 61 to 81) participated in the study, randomly assigned to each of four, 14-member groups. The description group received only a general overview of an ATM; the text guide group received written instructions for performing various transactions on an ATM; the pictorial guide group received written instructions accompanied by pictures of corresponding ATM screens; and the online tutorial group completed a step-by-step tutorial on a simulated ATM. Participants practiced on an ATM simulator. They were tested after a 24-h interval on their ability to perform familiar transactions on an unfamiliar ATM simulator and to perform completely novel transactions. Accuracy was best for the online tutorial group, intermediate for the text and pictorial guide groups, and worst for the description group. These data demonstrate both the importance of providing older adults with ATM training and the fact that the type of training influences the level of performance. The online tutorial. which provided specific practice on the task components, best facilitated acquisition and transfer performance.

The purpose of this study was to analyze automatic teller machine (ATM) usage across the adult life span. We conducted an extensive survey of 9000 people in the Memphis and Atlanta metropolitan areas. Approximately 17% of those people responded. The survey assessed detailed demographic information, experience with technology in general, experience specifically related to ATMs, problems and dislikes with ATMs, and reasons that people do not use ATMs. The survey provided a valuable set of data. First, we have detailed information about the demographics and individual characteristics of ATM users and nonusers; importantly, these data are stratified across the adult life span. In addition, we know the likes and dislikes of ATM users and the types of problems they typically have using ATMs. Moreover, we have a detailed analysis of why adults of all ages may choose not to use ATMs. Training and design implications of these data are discussed.

BACKGROUND: Several years in advance of the 2015 endpoint for the Millennium Development Goals (MDGs), Malawi was already thought to be one of the few countries in sub-Saharan Africa likely to meet the MDG 4 target of reducing under-5 mortality by two-thirds between 1990 and 2015. Countdown to 2015 therefore selected the Malawi National Statistical Office to lead an in-depth country case study, aimed mainly at explaining the country's success in improving child survival. METHODS: We estimated child and neonatal mortality for the years 2000-14 using five district-representative household surveys. The study included recalculation of coverage indicators for that period, and used the Lives Saved Tool (LiST) to attribute the child lives saved in the years from 2000 to 2013 to various interventions. We documented the adoption and implementation of policies and programmes affecting the health of women and children, and developed estimates of financing. FINDINGS: The estimated mortality rate in children younger than 5 years declined substantially in the study period, from 247 deaths (90% CI 234-262) per 1000 livebirths in 1990 to 71 deaths (58-83) in 2013, with an annual rate of decline of 5·4%. The most rapid mortality decline occurred in the 1-59 months age group; neonatal mortality declined more slowly (from 50 to 23 deaths per 1000 livebirths), representing an annual rate of decline of 3·3%. Nearly half of the coverage indicators have increased by more than 20 percentage points between 2000 and 2014. Results from the LiST analysis show that about 280,000 children's lives were saved between 2000 and 2013, attributable to interventions including treatment for diarrhoea, pneumonia, and malaria (23%), insecticide-treated bednets (20%), vaccines (17%), reductions in wasting (11%) and stunting (9%), facility birth care (7%), and prevention and treatment of HIV (7%). The amount of funding allocated to the health sector has increased substantially, particularly to child health and HIV and from external sources, but remains below internationally agreed targets. Key policies to address the major causes of child mortality and deliver high-impact interventions at scale throughout Malawi began in the late 1990s and intensified in the latter half of the 2000s and into the 2010s, backed by health-sector-wide policies to improve women's and children's health. INTERPRETATION: This case study confirmed that Malawi had achieved MDG 4 for child survival by 2013. Our findings suggest that this was achieved mainly through the scale-up of interventions that are effective against the major causes of child deaths (malaria, pneumonia, and diarrhoea), programmes to reduce child undernutrition and mother-to-child transmission of HIV, and some improvements in the quality of care provided around birth. The Government of Malawi was among the first in sub-Saharan Africa to adopt evidence-based policies and implement programmes at scale to prevent unnecessary child deaths. Much remains to be done, building on this success and extending it to higher proportions of the population and targeting continued high neonatal mortality rates. FUNDING: Bill & Melinda Gates Foundation, WHO, The World Bank, Government of Australia, Government of Canada, Government of Norway, Government of Sweden, Government of the UK, and UNICEF.