1 AUC Estimation The area under the ROC curve can be approximated using lower rectangles, upper rectangles or by using a linear approximation, as shown in Figure 1. The expressions related to each of these approximations are Al(zA) = M−1 ∑ t=0 (1− M̂Rt)(F̂ARt+1 − F̂ARt) Au(zA) = M−1 ∑ t=0 (1− M̂Rt+1)(F̂ARt+1 − F̂ARt) Am(zA) = M−1 ∑ t=0 (1− M̂Rt + M̂Rt+1 2 )(F̂ARt+1 − F̂ARt). Substituting the estimates fo...

background and objective: preterm birth occurs in 8% to 11% of all pregnancies and is responsible for 75% to 80% of all neonatal deaths. cytokines may be involved in the etiology of preterm birth through their stimulation of prostaglandin synthesis. cytokines may be released intocervicovaginal fluid during the breakdown of the chorio-decidual adhesion or from an inflammatory reaction in the sam...

BACKGROUND The Society of Thoracic Surgeons Predicted Risk of Mortality (PROM) score is a well-validated predictor of 30-day mortality after cardiac procedures. This study investigated the ability of PROM to predict longer-term survival. METHODS From January 1, 1996, to December 31, 2009, 24,222 patients with PROM scores underwent cardiac procedures at an academic center. Long-term all-cause ...

Receiver operating characteristic (ROC) curve is widely applied in measuring discriminatory ability of diagnostic or prognostic tests. This makes the ROC analysis one of the most active research areas in medical statistics. Many parametric and semiparametric estimation methods have been proposed for estimating the ROC curve and its functionals. In this paper, we propose the Bayesian bootstrap (...

BACKGROUND Breastfeeding self-efficacy can be measured with the Breastfeeding Self-Efficacy Scale-Short Form (BSES-SF). Mothers with low BSES-SF scores stop exclusive breastfeeding prematurely, but specific interventions can prevent that undesirable outcome. Because those interventions can be expensive, often one must decide which mothers will receive them. For that purpose, a cut-off BSES-SF s...

Area under an ROC curve plays an important role in estimating discrimination performance – a well-known theorem by Green (1964) states that ROC area equals the percentage of correct in two-alternative forcedchoice setting. When only single data point is available, the upper and lower bound of discrimination performance can be constructed based on the maximum and minimum area of legitimate ROC c...

BACKGROUND Teenage pregnancy is a known social problem which has been previously described using a number of deprivation measures. This study aimed to explore the temporal patterns of teenage pregnancy in Aberdeen, Scotland and to assess the discriminating ability of three measures of socioeconomic status. METHODS This was a population-based study from 1950 to 2010, using data from the Aberde...

AIMS To determine the clinical performance of three cerebrospinal fluid (CSF) IgG synthesis formulae using data obtained from two quantitation methods. METHODS Receiver operator characteristic (ROC) analysis and decision index plots were used to compare a rate nephelometric (RN) and a rocket immunoelectrophoretic (RIEP) method for quantitating albumin and IgG for use in CSF IgG synthesis form...

OBJECTIVE To use receiver operator characteristic curve methodology to determine the test characteristics of microscopic hematuria for identifying urologic injuries in children who underwent computed tomography (CT) of the abdomen and pelvis as part of a trauma evaluation. METHODS We performed a retrospective medical record review of all children from 0 to 12 years of age who presented to our...

BACKGROUND This study validates the accuracy of the Injury Severity Score (ISS) and the New Injury Severity Score (NISS) systems for prediction of need intubatin (NI), need mechanical ventilation (NMV), and duration of mechanical ventilation (DMV) in intensive care unit (ICU) trauma patient admissions. METHODS One-hundred ten trauma patients were included in this prospective cohort study. The...