Publications by authors named "Bradley E Huitema"

Time-series intervention designs that include two or more phases have been widely discussed in the healthcare literature for many years. A convenient model for the analysis of these designs has a linear model part (to measure changes in level and trend) plus a second part that measures the random error structure; the error structure is assumed to follow an autoregressive time-series process. Traditional generalized linear model approaches widely used to estimate this model are less than satisfactory because they tend to provide substantially biased intervention tests and confidence intervals.

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Methods for the analysis of one-factor randomized groups designs with ordered treatments are well established, but they do not apply in the case of more complex experiments. This article describes ordered treatment methods based on maximum-likelihood and robust estimation that apply to designs with clustered data, including those with a vector of covariates. The contrast coefficients proposed for the ordered treatment estimates yield higher power than those advocated by Abelson and Tukey; the proposed robust estimation method is shown (using theory and simulation) to yield both high power and robustness to outliers.

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For over a decade, the failure to reproduce findings in several disciplines, including the biomedical, behavioral, and social sciences, have led some authors to claim that there is a so-called "replication (or reproducibility) crisis" in those disciplines. The current article examines: (a) various aspects of the reproducibility of scientific studies, including definitions of reproducibility; (b) published concerns about reproducibility in the scientific literature and public press; (c) variables involved in assessing the success of attempts to reproduce a study; (d) suggested factors responsible for reproducibility failures; (e) types of validity of experimental studies and threats to validity as they relate to reproducibility; and (f) evidence for threats to reproducibility in the behavior science/analysis literature. Suggestions for improving the reproducibility of studies in behavior science and analysis are described throughout.

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Purpose: The present study had 3 objectives: (1) to evaluate the effects of 2 different interventions (feedback regarding customer satisfaction with wait time and combined feedback and goal setting) on wait time in a hospital outpatient pharmacy; (2) to assess the extent to which the previously applied interventions maintained their effects; and (3) to evaluate the differences between the effects of the original study and those of the present follow-up study.

Subjects And Methods: Participants were 10 employees (4 pharmacists and 6 technicians) of an outpatient pharmacy. Wait times and customer satisfaction ratings were collected for "waiting customers.

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Background: Although observational studies are popular, little has been done to study the integrity of human observers and the data collection process. Issues of data collection integrity threaten functional findings, leading to problematic interpretation and decreased replication. In our study the response effort associated with hand hygiene data collection in a hospital setting was manipulated using an altered data collection tool.

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Pedestrians account for 40-50% of traffic fatalities in large cities. Several previous studies based on relatively small samples have concluded that Pedestrian Countdown Timers (PCT) may reduce pedestrian crashes at signalized intersections, but other studies report no reduction. The purposes of the present article are to (1) describe a new methodology to evaluate the effectiveness of introducing PCT signals and (2) to present results of applying this methodology to pedestrian crash data collected in a large study carried out in Detroit, Michigan.

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Purpose: The purpose of this study was to compare the effects of 2 different interventions on wait times at a hospital outpatient pharmacy: (1) giving feedback to employees about customer satisfaction with wait times and (2) giving a combined intervention package that included giving more specific feedback about actual wait times and goal setting for wait time reduction in addition to the customer satisfaction feedback. The relationship between customer satisfaction ratings and wait times was examined to determine whether wait times affected customer service satisfaction.

Subjects And Methods: Participants were 10 employees (4 pharmacists and 6 technicians) of an outpatient pharmacy.

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A new portmanteau test for autocorrelation among the errors of interrupted time-series regression models is proposed. Simulation results demonstrate that the inferential properties of the proposed Q(H-M) test statistic are considerably more satisfactory than those of the well known Ljung-Box test and moderately better than those of the Box-Pierce test. These conclusions generally hold for a wide variety of autoregressive (AR), moving averages (MA), and ARMA error processes that are associated with time-series regression models of the form described in Huitema and McKean (2000a, 2000b).

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Effects of prior exposure to the experimental chamber with levers present or absent and variable-time (VT) 60-s water deliveries arranged during one, five, or no 1-hr sessions were examined in rats during a 6-hr response-acquisition session in which presses on one lever produced water delivery immediately or after a 15-s resetting delay, and presses on the other lever canceled scheduled water deliveries. Response acquisition was (a) slower to occur when water deliveries were delayed, (b) most consistent in groups that had received five VT sessions, and (c) impaired by the presence of levers only when there had been five VT sessions and water deliveries were delayed during the acquisition session.

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