An integrated‐likelihood‐ratio confidence interval for a proportion based on underreported and infallible data

2021 ◽  
Author(s):  
Briceön Wiley ◽  
Chris Elrod ◽  
Phil D. Young ◽  
Dean M. Young
Keyword(s):  
Confidence Interval ◽  
Likelihood Ratio ◽  
Integrated Likelihood

scholarly journals Prospective validation of Canadian TIA Score and comparison with ABCD2 and ABCD2i for subsequent stroke risk after transient ischaemic attack: multicentre prospective cohort study

BMJ ◽  
2021 ◽  
pp. n49
Author(s):  
Jeffrey J Perry ◽  
Marco L A Sivilotti ◽  
Marcel Émond ◽  
Ian G Stiell ◽  
Grant Stotts ◽  
...  
Keyword(s):  
Emergency Department ◽  
Cohort Study ◽  
Carotid Artery ◽  
Confidence Interval ◽  
Carotid Endarterectomy ◽  
Likelihood Ratio ◽  
Transient Ischaemic Attack ◽  
Carotid Artery Stenting ◽  
Stroke Risk ◽  
Ischaemic Attack

Abstract Objective To validate the previously derived Canadian TIA Score to stratify subsequent stroke risk in a new cohort of emergency department patients with transient ischaemic attack. Design Prospective cohort study. Setting 13 Canadian emergency departments over five years. Participants 7607 consecutively enrolled adult patients attending the emergency department with transient ischaemic attack or minor stroke. Main outcome measures The primary outcome was subsequent stroke or carotid endarterectomy/carotid artery stenting within seven days. The secondary outcome was subsequent stroke within seven days (with or without carotid endarterectomy/carotid artery stenting). Telephone follow-up used the validated Questionnaire for Verifying Stroke Free Status at seven and 90 days. All outcomes were adjudicated by panels of three stroke experts, blinded to the index emergency department visit. Results Of the 7607 patients, 108 (1.4%) had a subsequent stroke within seven days, 83 (1.1%) had carotid endarterectomy/carotid artery stenting within seven days, and nine had both. The Canadian TIA Score stratified the risk of stroke, carotid endarterectomy/carotid artery stenting, or both within seven days as low (risk ≤0.5%; interval likelihood ratio 0.20, 95% confidence interval 0.09 to 0.44), medium (risk 2.3%; interval likelihood ratio 0.94, 0.85 to 1.04), and high (risk 5.9% interval likelihood ratio 2.56, 2.02 to 3.25) more accurately (area under the curve 0.70, 95% confidence interval 0.66 to 0.73) than did the ABCD2 (0.60, 0.55 to 0.64) or ABCD2i (0.64, 0.59 to 0.68). Results were similar for subsequent stroke regardless of carotid endarterectomy/carotid artery stenting within seven days. Conclusion The Canadian TIA Score stratifies patients’ seven day risk for stroke, with or without carotid endarterectomy/carotid artery stenting, and is now ready for clinical use. Incorporating this validated risk estimate into management plans should improve early decision making at the index emergency visit regarding benefits of hospital admission, timing of investigations, and prioritisation of specialist referral.

scholarly journals On the Correction of the Asymptotic Distribution of the Likelihood Ratio Statistic If Nuisance Parameters Are Estimated Based on an External Source

2014 ◽  
Vol 10 (2) ◽  
Author(s):  
Marianne Jonker ◽  
Aad Van der Vaart
Keyword(s):  
Confidence Interval ◽  
Asymptotic Distribution ◽  
Confidence Intervals ◽  
Likelihood Ratio ◽  
Statistical Models ◽  
Likelihood Ratio Statistic ◽  
External Source ◽  
Nuisance Parameters ◽  
Testing Hypotheses

AbstractIn practice, nuisance parameters in statistical models are often replaced by estimates based on an external source, for instance if estimates were published before or a second dataset is available. Next these estimates are assumed to be known when the parameter of interest is estimated, a hypothesis is tested or confidence intervals are constructed. By this assumption, the level of the test is, in general, higher than supposed and the coverage of the confidence interval is too low. In this article, we derive the asymptotic distribution of the likelihood ratio statistic if the nuisance parameters are estimated based on a dataset that is independent of the data used for estimating the parameter of interest. This distribution can be used for correctly testing hypotheses and constructing confidence intervals. Four theoretical and practical examples are given as illustration.

Confidence Intervals for Weibull Fast-Fracture Parameters

2002 ◽  
Author(s):  
Mandar Chati ◽  
Curtis Johnson ◽  
Ahmet Kaya ◽  
Bjoern Schenk
Keyword(s):  
Confidence Interval ◽  
Confidence Intervals ◽  
Likelihood Ratio ◽  
Failure Modes ◽  
Bootstrap Method ◽  
Parametric Bootstrap ◽  
Nonparametric Bootstrap ◽  
Weibull Parameters ◽  
Fracture Data ◽  
Fast Fracture

Practical limits on number of specimens that can be tested lead to uncertainty in the estimated Weibull parameters. This paper presents an evaluation of four techniques for estimating confidence intervals for size-scaled Weibull parameters of monolithic ceramics. The techniques include normal approximation method, likelihood ratio technique, nonparametric bootstrap, and parametric bootstrap methods. For uncensored fast-fracture data, the confidence intervals for Weibull parameters are compared to the method used in ASTM Standard C1239. A simulation fracture experiment is conducted to evaluate the statistical characteristics, in particular coverage probability, of the four methods. For fast-fracture data with multiple failure modes, the statistical assessment of the confidence interval techniques for size-scaled Weibull parameters complement the existing literature. Overall, it was observed that the likelihood ratio technique and parametric bootstrap method perform very well. These techniques can also be extended for confidence interval estimation using fast-fracture data obtained from various geometry’s of test specimens and/or loading conditions (pooled data).

A Conservative Confidence Interval for a Likelihood Ratio

1971 ◽  
Vol 66 (336) ◽  
pp. 861-866
Author(s):  
Ann F. S. Mitchell ◽  
Clive D. Payne
Keyword(s):  
Confidence Interval ◽  
Likelihood Ratio

scholarly journals Validity of Musculoskeletal Ultrasound for Identification of Humeroradial Joint Chondral Lesions: A Preliminary Investigation

2014 ◽  
Vol 49 (1) ◽  
pp. 7-14
Author(s):  
Chelsea M. Lohman ◽  
Michael P. Smith ◽  
Gregory S. Dedrick ◽  
Jean-Michel Brismée
Keyword(s):  
Confidence Interval ◽  
Likelihood Ratio ◽  
Predictive Value ◽  
Musculoskeletal Ultrasound ◽  
Reference Standard ◽  
Single Image ◽  
Intrarater Reliability ◽  
Chondral Lesions ◽  
Macroscopic Examination ◽  
Rule Out

Context: Epicondylalgia is a common condition involving pain-generating structures such as tendon, neural, and chondral tissue. The current noninvasive reference standard for identifying chondral lesions is magnetic resonance imaging. Musculoskeletal ultrasound (MUS) may be an inexpensive and effective alternative. Objective: To determine the intrarater reliability and validity of MUS for identifying humeroradial joint (HRJ) chondral lesions. Design: Cross-sectional study. Setting: Clinical anatomy research laboratory. Patients or Other Participants: Twenty-eight embalmed cadavers (14 women, 14 men; mean age = 79.5 ± 8.5 years). Main Outcome Measure(s): An athletic trainer performed MUS evaluation of each anterior and distal-posterior capitellum and radial head to identify chondral lesions. The reference standard was identification of chondral lesions by gross macroscopic examination. Intrarater reliability for reproducing an image was calculated using the intraclass correlation coefficient (3,k) for measurements of the articular surface using 2 images. Intrarater reliability to evaluate a single image was calculated using the Cohen κ for agreement as to the presence of chondral lesions. Validity was calculated using the agreement of MUS images and gross macroscopic examination. Results: Intrarater reliability was 0.88 (95% confidence interval = 0.77, 0.94) for reproducing an image and 0.93 (95% confidence interval = 0.80, 1.06) for evaluating a single image. Identifying chondral lesions on all HRJ surfaces with MUS demonstrated sensitivity = 0.93, specificity = 0.28, positive predictive value = 0.58, negative predictive value = 0.77, positive likelihood ratio = 1.28, and negative likelihood ratio = 0.27. Conclusions: Musculoskeletal ultrasound is a reliable and sensitive tool for a clinician with relatively little experience and training to rule out HRJ chondral lesions. These results may assist with clinical assessment and decision making in patients with lateral epicondylalgia to rule out HRJ chondral lesions.

Is Gadoxetic Acid Disodium (Gd-EOB-DTPA)-Enhanced Magnetic Resonance Imaging an accurate diagnostic method for Hepatocellular Carcinoma? a systematic review with meta-analysis

2021 ◽  
Vol 17 ◽  
Author(s):  
Wang Yinzhong ◽  
Tian Xiaoxue ◽  
Tian Jinhui ◽  
Yang Pengcheng ◽  
Liu Xiaoying ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Systematic Review ◽  
Confidence Interval ◽  
Likelihood Ratio ◽  
Meta Analysis ◽  
Diagnostic Technique ◽  
Diagnostic Value ◽  
Lesion Studies ◽  
Weighted Values ◽  
Patient Studies

Background: Gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA) has become a widely used liver-specific contrast agent worldwide, but its value and limitations as a diagnostic technique with hepatocellular carcinoma (HCC), have not been assessed. Introduction: A review of the latest evidence available on the diagnostic value of Gd-EOB-DTPA-enhanced MRI for the evaluation of HCC is reported. Methods: A systematic, comprehensive literature search was conducted with PubMed, Scopus, EMBASE, the Web of Science, the Cochrane Library, CNKI, vip, wanfangdata and CBM from inception to June 31, 2020. The QUADAS-2 tool was used to evaluate the quality of the included studies. Pooled sensitivity (SEN), pooled specificity (SPE), pooled positive likelihood ratio (PLR), pooled negative likelihood ratio (NLR), pooled diagnostic odds ratio (dOR) and summary receiver operating characteristic (SROC) curves were calculated to assess the diagnostic value of the individual diagnostic tests. Results: A total of 47 articles were included, involving a total of 6362 nodules in 37 studies based on per-lesion studies. There were 13 per-patient studies, including a total of 1816 patients. The results of the meta-analysis showed that the per-lesion studies pooled weighted values were SEN 0.90 [95% confidence interval (CI): 0.87-0.92], SPE 0.92 (95%CI: 0.90-0.94), PLR 11.6 (95%CI: 8.8-15.2), NLR 0.11 (95%CI: 0.09-0.14) and dOR 107.0 (95%CI: 74.0-155.0). The AUC of the SROC curve was 0.96. The per-patient studies pooled weighted values were SEN 0.84 [95% confidence interval (CI): 0.78-0.89], SPE 0.92 (95%CI: 0.88-0.94), PLR 10.4 (95%CI: 7.4-14.6), NLR 0.17 (95%CI: 0.12-0.24) and dOR 61.0 (95%CI: 42.0-87.0). The AUC of the SROC curve was 0.95 and subgroup analyses were performed. Conclusions: The diagnostic value of Gd-EOB-DTPA for HCC was quantitatively evaluated in a per-lesion study and a per-patient study using a systematic review of the literature. A positive conclusion was drawn: Gd-EOB-DTPA-enhanced imaging is a valuable diagnostic technique for HCC. The size of the nodules and the selection of the imaging diagnostic criteria may affect the diagnostic sensitivity.

scholarly journals The value of ultrasound in diagnosis of pneumoperitoneum in emergent or critical conditions: A meta-analysis

2018 ◽  
Vol 26 (2) ◽  
pp. 111-117 ◽  
Author(s):  
Libing Jiang ◽  
Jing Wu ◽  
Xia Feng
Keyword(s):  
Confidence Interval ◽  
Likelihood Ratio ◽  
Meta Analysis ◽  
Characteristic Curve ◽  
Positive Likelihood Ratio ◽  
Negative Likelihood Ratio ◽  
Abdominal Ultrasound ◽  
Critical Conditions ◽  
Cochrane Library ◽  
Summary Receiver Operating Characteristic

Background: Hollow organs perforation is a life-threatening condition. Early diagnosis and emergent intervention are important. Bedside ultrasound may be an alternative diagnostic tool for this condition. Objective: The aim of this study was to explore the diagnostic value of ultrasound of pneumoperitoneum in emergent or critical conditions through meta-analysis. Methods: PubMed, EMBASE, and Cochrane Library were systematically searched for potential studies. Then, two reviewers performed the processes of study selection, data extraction, and quality assessment independently. Finally, diagnostic indexes were analyzed with STATA 12.0 software (Serial No. 40120519635). Results: A total of five studies with moderate to high quality were eligible for meta-analysis. The pooled sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio and their 95% confidence interval were 0.91 (95% confidence interval = 0.86–0.94), 0.96 (95% confidence interval = 0.75–0.99), 22.05 (95% confidence interval = 3.10–156.96), and 0.10 (95% confidence interval = 0.07–0.15), respectively. The area under the summary receiver operating characteristic curve was 0.92 (95% confidence interval = 0.90–0.94). Conclusion: Abdominal ultrasound is a useful alternative tool in diagnosing of pneumoperitoneum. However, due to limited evidence, it is not yet indicated for routine clinical use.

scholarly journals External validation of STONE, modified STONE, and CHOKAI scores for the diagnosis of ureteral stones in the Turkish population

2020 ◽  
pp. 102490792094547 ◽  
Author(s):  
Yahya Ayhan Acar ◽  
Emin Uysal
Keyword(s):  
Confidence Interval ◽  
Likelihood Ratio ◽  
Predictive Value ◽  
External Validation ◽  
Positive Likelihood Ratio ◽  
Negative Likelihood Ratio ◽  
Scoring Systems ◽  
Turkish Population ◽  
Ureteral Stones ◽  
Risk Patients

Background: Scoring systems seem to be effective in the management of patients with uncomplicated ureteral stones. However, their efficiency may differ by population. Objectives: We aimed to validate STONE, modified STONE, and CHOKAI scores for the diagnosis of ureteral stones in the Turkish population. Methods: We conducted a retrospective chart review between 01 February 2018 and 30 November 2018, in an academic emergency department. Demographics, laboratory findings, and radiologic tests of patients with flank pain were obtained. Computed tomography was used as the gold standard for the diagnosis of ureteral stones. STONE, modified STONE, and CHOKAI scores were calculated for each patient. The performance of the scoring systems was compared in terms of their specificity, sensitivity, positive likelihood ratio, negative likelihood ratio, negative predictive value, and positive predictive value. Results: A total of 157 patients were included in the study. The mean age was 38.47 ± 14.87 years, and 103 (65.6%) of the patients were males. The prevalence of ureteral stones was 84.0%, 88.9%, and 85.0% in the high-risk patients and 12%, 9.4%, and 22.7% in the low-risk patients for the STONE, modified STONE, and CHOKAI scores, respectively. Area under the curve values for the STONE, modified STONE, and CHOKAI scores were 0.776 (p = 0.001; 0.692–0.860 95% confidence interval), 0.825 (p < 0.001; 0.749–0.901 95% confidence interval), and 0.869 (p < 0.001; 0.806–0.932 95% confidence interval), respectively. The specificity and sensitivity values of STONE, modified STONE, and CHOKAI scores for the diagnosis of ureteral stones were 64.71, 71.70; 70.59, 87.74; and 66.67, 90.57, respectively. Conclusion: The CHOKAI score displayed the best performance compared to STONE and modified STONE in diagnosing ureteral stones in the Turkish population.

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