A general linear model for estimating effect size in the presence of publication bias

When the process of publication favors studies with smallp-values, and hence large effect estimates, combined estimates from many studies may be biased. This paper describes a model for estimation of effect size when there is selection based on one-tailedp-values. The model employs the method of maximum likelihood in the context of a mixed (fixed and random) effects general linear model for effect sizes. It offers a test for the presence of publication bias, and corrected estimates of the parameters of the linear model for effect magnitude. The model is illustrated using a well-known data set on the benefits of psychotherapy.Authors' note: The contributions of the authors are considered equal, and the order of authorship was chosen to be reverse-alphabetical.     

Effects of models and demonstrations of personal narratives on the use of lexical ties by writers with mental retardation

A single subject reversal design was used to investigate the effects of two methods for teaching writing to eight adolescents with mild or moderate mental retardation during a weekly process writing workshop. During each workshop, each student wrote a personal narrative while the teacher circulated among the group and provided positive verbal feedback and spelled words on request. Students' texts were later typed with corrected spelling and punctuation and returned to them with verbal praise before the next writing workshop. During the first experimental condition, the subjects listened to an exemplar text selected by the teacher. In the second phase, the teacher read a narrative she had written as the exemplar text. During the third experimental condition, the teacher orally self-instructed herself through steps in writing a narrative. The subjects' texts were analyzed for number of words written and number and type of lexical ties used to produce cohesion between sentences in a text. The model narrative produced the best gains in the number of words written by the poorer readers, while the demonstration improved the cohesiveness of their texts. The better readers and writers wrote more cohesively during the model narrative and produced longer text during the demonstration condition.     

A note on analyzing ordered alternatives

A general method of devising stepwise multiple testing procedures with fixed experimentwise error is applied to the problem of non-parametric randomized block design with ordered alternatives. In addition, the method is applied to other models with ordered alternatives.The author wishes to thank the referees for helpful suggestions.     

Stimulus control of respondent and operant key pecking: A single key procedure

Pigeons' responses to a uniformly illuminated response key were either reinforced on a variable-interval one-minute schedule of reinforcement or extinguished for one-minute periods. When 1.5 second signals were presented at the beginning of each component, so as to differentially predict reinforcement, the pigeons pecked at the signals, at rates higher than rates during the remainder of the component. When the brief signals were not differentially predictive of reinforcement, pecking in their presence decreased to near zero levels. Similar results were obtained with signals based upon colors and upon line orientations. Changes in rates of (unreinforced) pecking occurred during the signal whether pigeons responded differentially during the remainder of the component or not. Experiment II demonstrated that the presence of the signal correlated with extinction was not necessary for pecking to develop at the signal which preceded the component in which responding was intermittently reinforced. The experiments demonstrated a clear dissociation of respondent control from operant control of a response. In addition, operant behavior was shown to be relatively insensitive to differing rates of reinforcement, as compared to the sensitivity of respondent behavior to differing rates of reinforcement produced by the very same operant behavior.     

Probability of directional errors with disordinal (qualitative) interaction

In a factorial design with two or more factors, there is nonzero interaction when the differences among the levels of one factor vary with levels of other factors. The interaction is disordinal or qualitative with respect to a specific factor, sayA, if the difference between at least two levels ofA is positive for some and negative for some levels of the other factors. Using standard methods of analysis, there is a potentially large probability of drawing incorrect conclusions about the signs of differences in the presence of disordinal interaction. The maximum probability of such incorrect conclusions, or directional errors, is derived for two-factor designs in which the factor of interest has two levels and the number of levels of the other factor varies.     

Peer tutoring among elementary students: educational benefits to the tutor

To determine whether tutoring might be academically beneficial to the tutor, this study investigated the acquisition of spelling words by three elementary students in a peer tutoring program. The experimental design allowed a simultaneous comparison of each child's gain in performance on comparable word lists on which the child tutored another child, was tutored by another child, or neither gave nor received tutoring. The children's spelling improved nearly an equivalent amount on those words on which they tutored another child as on the words on which they were tutored; no such change was noted on the words on which they neither gave nor received tutoring. These findings, that peer tutoring is profitable for the tutor as well as the tutee, provide a basis for recommending peer tutoring as one method of individualizing education.     

A multi-element analysis of the effect of teacher aides in an "open"-style classroom

Open classrooms with few rules, individualized instruction, and informal class organization present new problems for the application of behavior principles. The effects of three types of teacher aides on student achievement and on-task behavior were studied. Each was compared with a standard no-aide condition. Subjects were 54 third graders in two "open"-style classrooms. The three types of aide, helping adult, disciplinary adult, and helping fifth-grade aide, were compared in a multi-element design with a no-aide control. The helping-adult aide significantly affected the academic output of the class, when compared with the no-aide condition. All aide conditions produced more academic work and on-task behavior than did the standard no-aide condition.     

Time-series analysis in operant research

A time-series method is presented, nontechnically, for analysis of data generated in individual-subject operant studies, and is recommended as a supplement to visual analysis of behavior change in reversal or multiple-baseline experiments. The method can be used to identify three kinds of statistically significant behavior change: (a) changes in score levels from one experimental phase to another, (b) reliable upward or downward trends in scores, and (c) changes in trends between phases. The detection of, and reliance on, serial dependency (autocorrelation among temporally adjacent scores) in individual-subject behavioral scores is emphasized. Examples of published data from the operant literature are used to illustrate the time-series method.     

TEACHING COIN EQUIVALENCE TO THE MENTALLY RETARDED1

A program was designed to teach coin equivalence to mentally retarded adolescents. Coin equivalence was defined as choosing several different combinations of coins to equal specified target values. A pretest-posttest matched-groups design was employed with an experimental group receiving the monetary training, and a no-training control group. A multiple baseline across coin-counting responses was also incorporated in the experimental group. Training was divided into six stages, each teaching one specific method of combining coins to equal 10 target values from 5¢ through 50¢. A three-component response chain was used, requiring (a) naming, (b) selecting and counting, and (c) depositing target monetary values into a coin machine. Experimental subjects improved significantly in coin equivalence performance and maintained their skill on follow up tests; control subjects did not.     

INCREASING EXTENDED CARE FACILITY RESIDENTS' ATTENDANCE AT RECREATIONAL ACTIVITIES WITH CONVENIENT LOCATIONS AND PERSONAL INVITATIONS1

Residents of extended care facilities generally exhibit a low level of attendance at recreational and therapeutic activities. Spatial arrangement of rooms, prompting, snacks, and small prizes have been suggested as factors that affect attendance. The present study examined the effects of an extensive system of prompts and the location of activity areas on the attendance of residents at a variety of activities. Twenty-six subjects were randomly selected from the ambulatory population of the facility. The first time each subject entered the activity room during the first 6 min of an activity session their name was recorded. Reliability measures were taken at 10 sessions, with a 95% mean agreement between observers. The variables examined were the amount of individualization of subjects (experimental group I: names announced versus experimental group 2: names not announced), room location (central or peripheral), use of names in announcements (activity only versus activity and group I names), and mode of announcement (PA system only versus PA system and in-person). A counter-balanced group design with repeated measures was used, with a randomly determined order of application of experimental treatments. An analysis of variance split plot 2.222 (Kirk, R. E. Experimental Design: Procedures for the Behavioral Science. Belmont, Ca.: Brooks-Cole, 1968.) of the level of subject attendance yielded significant main effects for room location, F(1, 24) = 5.47, p < 0.05, and type of announcement, F(1, 24) = 9.10, p < 0.01, and significant interactions for Individualization × Use of Names in Announcements, F(1, 24) = 5.57, p < 0.05, and Room Location × Mode of Announcement, F(1, 24) = 7.90, p < 0.01. The results indicate that using a centrally located room and announcement of resident names increases attendance at a variety of activities. The increased social and environmental interaction generated by activity attendance has potential therapeutic benefits for the residents involved. Furthermore, the kind of information reported here and by others should be taken into consideration by planners of a variety of group living facilities, ranging from nursing homes to residential treatment cottages.