Statistical Tests of Type I Error

2021 ◽  
pp. 90-120
Author(s):  
Charles Auerbach
Keyword(s):  
Control Charts ◽  
Sampling Error ◽  
Statistical Tests ◽  
Statistical Significance ◽  
Data Sets ◽  
Chi Square ◽  
Statistical Process ◽  
Incorrect Decision ◽  
Type 1 Error ◽  
Statistical Process Control Charts

This chapter covers tests of statistical significance that can be used to compare data across phases. These are used to determine whether observed outcomes are likely the result of an intervention or, more likely, the result of sampling error or chance. The purpose of a statistical test is to determine how likely it is that the analyst is making an incorrect decision by rejecting the null hypothesis, that there is no difference between compared phases, and accepting the alternative one, that true differences exist. A number of tests of significance are presented in this chapter: statistical process control charts (SPCs), proportion/frequency, chi-square, the conservative dual criteria (CDC), robust conservative dual criteria (RCDC), the t test, and analysis of variance (ANOVA). How and when to use each of these are also discussed, and examples are provided to illustrate each. The method for transforming autocorrelated data and merging data sets is discussed further in the context of utilizing transformed data sets to test of Type 1 error.

Analyzing Group Data

2021 ◽  
pp. 121-142
Author(s):  
Charles Auerbach
Keyword(s):  
Control Charts ◽  
Type I Error ◽  
Statistical Significance ◽  
Data Sets ◽  
Type I ◽  
Chi Square ◽  
Statistical Process ◽  
Incorrect Decision ◽  
Group Data ◽  
Statistical Process Control Charts

This chapter covers tests of statistical significance that can be used to compare data across phases. These are used to determine whether observed outcomes are likely the result of an intervention or, more likely, the result of chance. The purpose of a statistical test is to determine how likely it is that the analyst is making an incorrect decision by rejecting the null hypothesis and accepting the alternative one. A number of tests of significance are presented in this chapter: statistical process control charts (SPCs), proportion/frequency, chi-square, the conservative dual criteria (CDC), robust conservative dual criteria (RCDC), the t test, and analysis of variance (ANOVA). How and when to use each of these are also discussed. The method for transforming autocorrelated data and merging data sets is discussed. Once new data sets are created using the Append() function, they can be tested for Type I error using the techniques discussed in the chapter.

Patient Safety/Quality Improvement Primer, Part III: The Role of Simulation

2021 ◽  
pp. 019459982110133
Author(s):  
Ellen S. Deutsch ◽  
Sonya Malekzadeh ◽  
Cecelia E. Schmalbach
Keyword(s):  
Patient Safety ◽  
Quality Improvement ◽  
Control Charts ◽  
Neck Surgery ◽  
Resident Training ◽  
Statistical Process ◽  
Ensure Patient Safety ◽  
Statistical Process Control Charts ◽  
The Individual ◽  
The Impact

Simulation training has taken a prominent role in otolaryngology–head and neck surgery (OTO-HNS) as a means to ensure patient safety and quality improvement (PS/QI). While it is often equated to resident training, this tool has value in lifelong learning and extends beyond the individual otolaryngologists to include simulation-based learning for teams and health systems processes. Part III of this PS/QI primer provides an overview of simulation in medicine and specific applications within the field of OTO-HNS. The impact of simulation on PS/QI will be presented in an evidence-based fashion to include the use of run and statistical process control charts to assess the impact of simulation-guided initiatives. Last, steps in developing a simulation program focused on PS/QI will be outlined with future opportunities for OTO-HNS simulation.

Reducing Unnecessary Respiratory Viral Testing to Promote High-Value Care

PEDIATRICS ◽  
2022 ◽  
Author(s):  
Olivia Ostrow ◽  
Deena Savlov ◽  
Susan E. Richardson ◽  
Jeremy N. Friedman
Keyword(s):  
Control Charts ◽  
Respiratory Infections ◽  
Audit And Feedback ◽  
Improvement Strategy ◽  
Statistical Process ◽  
Process Control Charts ◽  
Statistical Process Control Charts ◽  
Viral Testing ◽  
Return Visits ◽  
Viral Respiratory Infections

BACKGROUND AND OBJECTIVES: Viral respiratory infections are common in children, and practice guidelines do not recommend routine testing for typical viral illnesses. Despite results often not impacting care, nasopharyngeal swabs for viral testing are frequently performed and are an uncomfortable procedure. The aim of this initiative was to decrease unnecessary respiratory viral testing (RVT) in the emergency department (ED) and the pediatric medicine wards (PMWs) by 50% and 25%, respectively, over 36 months. METHODS: An expert panel reviewed published guidelines and appropriate evidence to formulate an RVT pathway using plan-do-study-act cycles. A multifaceted improvement strategy was developed that included implementing 2 newer, more effective tests when testing was deemed necessary; electronic order modifications with force functions; audit and feedback; and education. By using statistical process control charts, the outcomes analyzed were the percentage of RVT ordered in the ED and the rate of RVT ordered on the PMWs. Balancing measures included return visits leading to admission and inpatient viral nosocomial outbreaks. RESULTS: The RVT rate decreased from a mean of 3.0% to 0.5% of ED visits and from 44.3 to 30.1 per 1000 patient days on the PMWs and was sustained throughout the study. Even when accounting for the new rapid influenza test available in the ED, a 50% decrease in overall ED RVT was still achieved without any significant impact on return visits leading to admission or inpatient nosocomial infections. CONCLUSIONS: Through implementation of a standardized, electronically integrated RVT pathway, a decrease in unnecessary RVT was successfully achieved. Audit and feedback, reminders, and biannual education all supported long-term sustainability of this initiative.

Use of Viscosity Standard Fluid To Control Quality of Rheological Measurements for Characterizing Asphalt Binders

1997 ◽  
Vol 1586 (1) ◽  
pp. 24-31
Author(s):  
Raj Dongré ◽  
Satish Ramaiah ◽  
John D’Angelo
Keyword(s):  
Control Charts ◽  
High Viscosity ◽  
Asphalt Binders ◽  
Rheological Parameters ◽  
Reference Laboratory ◽  
Statistical Process ◽  
Standard Material ◽  
Rheological Measurements ◽  
Statistical Process Control Charts ◽  
Repeatability And Reproducibility

The results of a study to establish a protocol for calibrating and maintaining Superpave rheometers are described. The reference standard material used was supplied by Cannon Instrument Co. The material (high viscosity standard) is designated as N2700000 and is supplied with ASTM traceable values of steady shear viscosity at various Superpave specification temperatures. The main objective was to determine whether sound calibration practices and adequate training can improve the repeatability and reproducibility of the rheological parameters required in the Superpave binder specification. Ten laboratories participated in the study. The results indicate that the viscosity standard can be used as a standard fluid to calibrate and maintain the Superpave rheometers. The repeatability and reproducibility data were compared with similar estimates reported by the AASHTO Materials Reference Laboratory. It was found that the reproducibility (between-laboratory variation) improved by a factor of two and repeatability (within-laboratory variation) improved modestly. With these results, a protocol for using the standard was also developed. Further analysis of results is under way to determine the frequency of calibration and maintenance required to obtain consistent rheological measurements. The results of this analysis and efforts to implement statistical process control charts for calibration and maintenance of rheometers using the standard reference fluid (Cannon N2700000 viscosity standard) are discussed.

Substitution of Generic Warfarin for Coumadin in an HMO Setting

2002 ◽  
Vol 36 (5) ◽  
pp. 764-768 ◽  
Author(s):  
Paul E Milligan ◽  
Gerald A Banet ◽  
Amy D Waterman ◽  
Susan K Gatchel ◽  
Brian F Gage
Keyword(s):  
Adverse Events ◽  
Control Charts ◽  
Health Maintenance Organization ◽  
Therapeutic Index ◽  
International Normalized Ratio ◽  
Rank Test ◽  
Statistical Process ◽  
Health Maintenance ◽  
Statistical Process Control Charts ◽  
Signed Rank Test

BACKGROUND: Substitution of generic warfarin for Coumadin presents safety concerns due to warfarin's narrow therapeutic index and because a prior generic formulation was removed from the US market after it was associated with adverse events. OBJECTIVE: To determine whether a health maintenance organization (HMO) can add generic warfarin to its formulary without adversely affecting warfarin management or increasing adverse events. DESIGN: In a prospective, observational study, an HMO that formerly dispensed only Coumadin added a generic warfarin preparation (Barr Laboratories, Pomona, NY) to its formulary. SETTING: An anticoagulation service (ACS) affiliated with an HMO that was based in St. Louis, MO. PARTICIPANTS: The cohort consisted of 182 enrollees in the ACS as of May 1, 1999. At the start of the study, these participants were taking Coumadin; by October 31, 2000, all had switched to Barr warfarin. MEASUREMENTS AND MAIN RESULTS: We collected data 8 months prior to and 10 months after the introduction of generic warfarin for the following endpoints: international normalized ratio (INR) control, frequency of INR monitoring, number of dose changes, and rate of thrombotic and hemorrhagic events. Statistical process control charts were used to differentiate between random variation in the endpoints and changes due to different warfarin formulations, and we used the Wilcoxon signed-rank test to look for a change in any endpoint after patients changed to generic warfarin. No significant differences were found in any endpoint. CONCLUSIONS: Substitution of Barr warfarin for Coumadin did not significantly affect INR control, warfarin management, or adverse events. Our findings suggest that HMOs can safely substitute at least 1 generic formulation of warfarin without extra monitoring.

scholarly journals Reducing Mother-to-Child Transmission of HIV Using Quality Improvement Approaches

2019 ◽  
Vol 18 ◽  
pp. 232595821985563
Author(s):  
Nigel Livesley ◽  
Astou Coly ◽  
Esther Karamagi ◽  
Tamara Nsubuga-Nyombi ◽  
Stella Kasindi Mwita ◽  
...  
Keyword(s):  
Quality Improvement ◽  
Control Charts ◽  
Hiv Transmission ◽  
Health Workers ◽  
Care Delivery ◽  
Care Quality ◽  
Data Systems ◽  
Statistical Process ◽  
Statistical Process Control Charts ◽  
Mother To Child

Over half of mother-to-child HIV transmission (MTCT) occurs postdelivery. Keeping mother–infant pairs in care remains challenging. Health workers in 3 countries used quality improvement (QI) approaches to improve data systems, mother–infant retention, and facility-based care delivery. The number and proportion of infants with known HIV status at time of discharge from early infant diagnosis programs increased in Tanzania and Uganda. We analyzed data using statistical process control charts. Mother-to-child HIV transmission did not decrease in 15 Kenyan sites, decreased from 12.7% to 3.8% in 28 Tanzanian sites, and decreased from 17.2% to 1.5% in 10 Ugandan sites with baseline data. This improvement is likely due to the combination of option B+, service delivery improvements, and retention through QI approaches. Reaching the global MTCT elimination target and maximizing infant survival will require health systems to support mother–infant pairs to remain in care and support health workers to deliver care. Quality improvement approaches can support these changes.

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