认知诊断缺失数据处理方法的比较：零替换、多重插补与极大似然估计法

数据缺失在测验中经常发生, 认知诊断评估也不例外, 数据缺失会导致诊断结果的偏差。首先, 通过模拟研究在多种实验条件下比较了常用的缺失数据处理方法。结果表明：(1)缺失数据导致估计精确性下降, 随着人数与题目数量减少、缺失率增大、题目质量降低, 所有方法的PCCR均下降, Bias绝对值和RMSE均上升。(2)估计题目参数时, EM法表现最好, 其次是MI, FIML和ZR法表现不稳定。(3)估计被试知识状态时, EM和FIML表现最好, MI和ZR表现不稳定。其次, 在PISA2015实证数据中进一步探索了不同方法的表现。综合模拟和实证研究结果, 推荐选用EM或FIML法进行缺失数据处理。     

Inferences about which of J dependent groups has the largest robust measure of location

Recently, a multiple comparisons procedure was derived with the goal of determining whether it is reasonable to make a decision about which of J independent groups has the largest robust measure of location. This was done by testing hypotheses aimed at comparing the group with the largest estimate to the remaining J − 1 groups. It was demonstrated that for the goal of controlling the familywise error rate, meaning the probability of one or more Type I errors, well-known improvements on the Bonferroni method can perform poorly. A technique for dealing with this issue was suggested and found to perform well in simulations. However, when dealing with dependent groups, the method is unsatisfactory. This note suggests an alternative method that is designed for dependent groups.     

A pharmacological examination of the resistance-to-change hypothesis of response strength.

The effects of d-amphetamine sulfate, sodium pentobarbital, haloperidol, and cholecystokinin-octapeptide were examined within the context of Nevin's (1974, 1979) resistance-to-change hypothesis of response strength. In three experiments, rats' responding was reinforced by delivery of food under chained random-interval 30-s random-interval 30-s, multiple fixed-interval 30-s fixed-interval 120-s, or multiple random-interval 30-s random-interval 120-s schedules. Each rat received several doses of each drug and changes in response rate were measured. The resistance-to-change hypothesis predicts greater disruption of response rate relative to baseline in the initial component of the chained schedule and in the 120-s component of the multiple schedules. In the chained schedule cholecystokinin-octapeptide produced greater reductions in response rate relative to baseline in the initial component. However, no differences between components were observed with haloperidol or sodium pentobarbital, and high doses of d-amphetamine reduced response rate in the terminal component relatively more than in the initial component. In the multiple schedules either no differences were observed between components or response rate was reduced more relative to baseline in the 30-s component. The data fail to support the notion that drugs may be viewed within the same context as other response disruptors such as extinction, satiation, and the presentation of alternative reinforcement.     

On the measurement of time allocation on multiple variable-interval schedules

Six pigeons were trained on a modified multiple-schedule procedure. In a three-key chamber, the center key was lighted red or green, depending upon which component schedule was in effect. A response on this key transferred this color to each of two side keys, and responses on one of those keys produced reinforcers according to the component schedule. After 2 s, the side-key lights were extinguished, the center key was reilluminated, and a further center-key response was required to give access, as before, to the component schedules. Components alternated every 3 min. This limited-access procedure allowed both times spent switched into the side keys and time spent not switched in to be measured in the two components. Component reinforcer rates were varied over eight experimental conditions. Both component response rate and component time allocation were increasing functions of relative component reinforcer rate, and these functions were not significantly different. This finding implies that local response rates (responses divided by time switched in) were unaffected by changing component reinforcer rates on multiple schedules. Because a similar result was recently obtained for concurrent schedules, models of multiple and concurrent-schedule performance may need to consider only the time allocation of behavior emitted at equal tempo in the component schedules.     

Human operant performance: Sensitivity and pseudosensitivity to contingencies

Undergraduates' button presses occasionally produced points exchangeable for money. Left and right buttons were initially correlated with multiple random-ratio (RR) and random-interval (RI) components, respectively. During interruptions of the multiple schedule, students filled out sentence-completion guess sheets describing the schedules, and points were contingent upon the accuracy of guesses. To test for sensitivity to schedule contingencies, schedule components were repeatedly reversed between the two buttons. Pressing rates were consistently higher in ratio than in interval components even when feedback for guesses was discontinued, demonstrating sensitivity to the difference between ratio and interval contingencies. The question was whether this sensitivity was based directly on the contingencies or whether it was rule-governed. For two students, when multiple RR RI schedules were changed to multiple RI RI schedules, rates became low in both components of the multiple RI RI schedule; however, subsequent prevention of point deliveries for the first few responses in any component produced high rates in that component. For a third student, response rates became higher in the RI component that provided the lower rate of reinforcement. In each case, performance was inconsistent with typical effects of the respective schedules with nonhuman organisms; it was therefore plausible to conclude that the apparently contingency-governed performances were instead rule-governed.     

ASSESSING CHOICE MAKING AMONG CHILDREN WITH MULTIPLE DISABILITIES

Some learners with multiple disabilities display idiosyncratic gestures that are interpreted as a means of making choices. In the present study, we assessed the validity of idiosyncratic choice-making behaviors of 3 children with multiple disabilities. Opportunities for each child to choose between food and drink were provided under two conditions. In one condition, the children were given the food or drink item corresponding to their prior choice. In the other condition, the teacher delivered the item opposite to that chosen. It was reasoned that valid choice-making behaviors would be reflected in a greater tendency to accept the chosen item and refuse the unchosen item. Direct observations revealed all children consistently indicated choices during both conditions. Choices of both the food and drink items were made by all 3 children. A reversal design demonstrated that acts of refusal were more frequent when choices were followed by delivery of the item opposite to that chosen. Similar assessment procedures may be effective in determining the function of idiosyncratic gestures exhibited by persons with multiple disabilities. For children lacking such skills, intervention to teach valid choice-making behaviors may be needed to complement assessment procedures.     

Behavioral contrast: Pavlovian effects and anticipatory contrast.

Two sources of behavioral contrast have been identified previously: Pavlovian stimulus-reinforcer relations and component sequence effects (anticipatory contrast). This study sought to isolate these sources of control procedurally in a four-ply multiple schedule composed of two fixed two-component sequences. Different cues were associated with the first component of each sequence, and contrast effects were studied in these target components. In Experiment 1, differential cuing of Component 2 between sequences and availability of reinforcement during target components were varied across three groups of pigeons; the stimulus-reinforcer relation between target-component cues and schedule of reinforcement in Component 2 was varied within subjects. Control by the Pavlovian relation was demonstrated under all conditions, and anticipatory contrast was not observed. In Experiment 2, target-component duration was systematically varied in the three groups of Experiment 1. Control by the Pavlovian relation was reliably obtained only when target-component behavior was unreinforced, and diminished with increases in component duration. Anticipatory contrast emerged in the two groups for which target-component reinforcement was available. These and other data indicate that Pavlovian effects in multiple schedules may be obscured when the requisite conditions for anticipatory contrast are present.     

Effects of self-generated rules on the development of schedule-controlled behavior.

College students responded under a multiple differential-reinforcement-of-low-rate 5-s fixed-ratio 8 schedule, with components alternating every 2 min. After 40 programmed minutes of acquisition and 12 min of maintenance, without notice, both schedules changed to extinction for 28 min. During acquisition, between alternations of the multiple schedule, some subjects were asked to develop rules describing the schedule contingencies. Other subjects were given these same rules between alternations, and a third group neither received nor were asked to develop rules. By the end of the acquisition phase, self-generated-rule subjects were more likely to show schedule-typical behavior than were subjects not asked to generate rules. The behavior of those given rules was similar to those asked to generate rules at the end of acquisition, but yoked-rule subjects acquired schedule-typical behavior at a quicker rate. By the end of extinction, during the period corresponding to the previous fixed-ratio interval, all no-rule subjects who had earned points during acquisition and maintenance were responding at a rate of less than 30 responses per minute. Only 3 of the 9 self-generated-rule subjects and 2 of the 5 yoked-rule subjects were similarly responding at this low rate. Results suggest that asking subjects to develop self-rules facilitates acquisition, but can retard extinction. Results also suggest that self-generated rules function similarly to external rules.     

Inverse relations between preference and contrast

Pigeons were trained on a multiple schedule in which two target components with identical reinforcement schedules were followed by either the same-valued schedule or by extinction. Response rate increased in both target components but was higher in the target component followed by extinction, replicating previous findings of positive anticipatory contrast. A similar design was used to study negative contrast, in that the two target components were followed either by the same-valued schedule or by a higher valued schedule. Negative contrast occurred equally, on average, in both target components, thus failing to demonstrate negative contrast that is specifically anticipatory in nature. When the stimuli correlated with the two target components were paired in choice tests, the pattern of preference was in the opposite direction. For the positive contrast procedure, no significant preference between the two target stimuli was evident. But for the negative contrast procedure, preference favored the stimulus followed by the higher valued schedule. The results demonstrate a functional dissociation between positive and negative contrast in relation to stimulus value. More generally, the results demonstrate an inverse relation between response rate and preference and challenge existing accounts of contrast in terms of the concept of relative value.     

Influence in canonical correlation analysis

The perturbation theory of the generalized eigenproblem is used to derive influence functions of each squared canonical correlation coefficient and the corresponding canonical vector pair. Three sample versions of these functions are described and some properties are noted. As particular applications, the influence function of the squared multiple correlation coefficient and influence functions of eigenvalues and eigenvectors in correspondence analysis are obtained. Three numerical examples are briefly discussed.We thank the Editor and the anonymous reviewers for their helpful comments. This research was carried out with the financial support of the Italian Ministry of the University and the National Research Council.