![]() Indicating that a stimulus is absent when it is actually present is called a miss, and indicating that a stimulus is present when it is actually absent is called a false alarm.Īccording to SDT, the behavior of an observer in this type of situation has at least two dimensions. Correctly indicating that a stimulus is present is called a hit, and correctly indicating that a stimulus is absent is called a correct rejection. In classical signal-detection experiments, the observer either responds “yes” or “no” regarding the presence of the signal on each trial. The task of the observer is to discriminate the presence versus absence of a stimulus (i.e., detect a signal against a background of noise). SDT was developed to examine the behavior of an observer in the presence of ambiguous stimuli. Signal-detection theory (SDT Green & Swets, 1966) may provide a useful framework for further analysis of observer accuracy. For example, sources of random error versus nonrandom error (i.e., observer bias) have not been differentiated in previous research. Furthermore, the nature of inconsistencies or inaccuracies in data collection was not systematically examined. A large portion of these studies, however, focused on interobserver agreement rather than accuracy. Research findings indicate that factors related to the measurement system (e.g., number of different behaviors scored), characteristics of the observers (e.g., duration of training), characteristics of the setting (e.g., presence of other observers), and consequences for scoring (e.g., social approval for recording changes in the level of the target behavior) can influence the accuracy and reliability of behavioral measurement (see Kazdin, 1977 Repp, Nieminen, Olinger, & Brusca, 1988, for reviews). Furthermore, agreement is not synonymous with accuracy (i.e., two observers could agree but incorrectly score the behavior Kazdin, 1977 Mudford, Martin, Hui, & Taylor, 2009).Ī number of studies have identified variables that might lead observers to record data inaccurately. However, practitioners do not routinely collect data on interobserver agreement (i.e., reliability). Interobserver agreement, which is determined by having two observers record the same events at the same time, is routinely reported in published research to provide some degree of confidence in the accuracy of the reported data. ![]() Little research has been conducted on the accuracy of data collected by direct-care staff or the best way to train people to collect these data. The behavioral consultant examines these data to obtain information that is key to program effectiveness, such as the baseline level of responding, the conditions under which a behavior occurs, and changes in responding with the introduction of treatment or modifications to existing procedures. ![]() In application, behavioral consultants often rely on parents, teachers, and direct-care staff to collect data on target behaviors. ![]() Trained observers use various methods to record occurrences of precisely defined target behaviors and other events during designated observational periods. Direct observation and measurement of behavior are the cornerstones of effective research and practice in applied behavior analysis. ![]()
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