Statistical process control and rehabilitation outcome: The single-subject design reconsidered.

Abstract

Memorial Medical CenterRehabilitation psychology embraces the scientist-practitioner model as its professional philosophy. This model's original intent was that the diagnosis and treatment of each individual case was to be regarded as a single and well-controlled experiment. Executing this ideal in rehabilitation has been problematic owing to practical, ethical, and technical concerns. Statistical process control (SPC), a robust, graphical analytic strategy developed in industry, is offered as a means to deploy single-subject designs on the front lines of rehabilitation. The history and construction of SPC control charts are presented followed by case examples relevant to rehabilitation practice (ambulation, depression, cognitive rehabilitation, agitation). SPC control charts are a time-tested, scientifically validated, and pragmatic tool to achieve and document patient outcomes.

The Effect of an Artificially Lengthened Vocal Tract on Estimated Glottal Contact Quotient in Untrained Male Voices

“…The time series data for each participant was analyzed using Statistical Process Control (SPC). [28][29][30][31] The data from all 15 participants were also treated as a group and a post hoc comparison of pre-, during, and posttube phonation CQ means was made using a repeated-measure analysis of variance (ANOVA). This was used to supplement the single-subject design analysis and help answer the questions of both treatment and posttreatment effects of tube phonation on glottal CQ.…”

“…Callahan and Barisa 28 have proposed the adoption of SPC for analyzing the data from single-subject behavioral studies. Developed in the 1920s and 1930s for industry, 31,40 SPC is both powerful and simple, and relies on sound statistical principles.…”

The process of basic training, applied training, maintaining the performance of an observer

“…One of the classical tools for evaluating statistically whether a series of data presents excessive variability is through statistical process control, also known as Shewhart charts, which were originally applied in the context of management and organizational research (Mawhinney, 1992). Statistical process control is also considered to provide an objective basis for decision making in studies that take longitudinal measures of an individual (Callahan & Barisa, 2005;Hantula, 1995). This technique combines graphical representation of the data with quantitative criteria, based on two of the main descriptive statistics: the mean and the standard deviation.…”

The Effect of Voice Amplification on Occupational Vocal Dose in Elementary School Teachers

“…These are explained in Wheeler's text, 29 and a simple tutorial in the application of SPC data analysis to human behavioral research has been written by Callahan and Barisa. 30 In essence, when points hover above and below the mean line, little effect can be attributed to changes in the process, whereas runs of points above or on the mean represent a moderate effect of the independent variable, and points close to or outside the control limits indicate a strong effect. It is evident on inspection of the control charts in Figure 1 that both intensity and distance dose decreased from baseline during the week of amplification for teacher 1.…”