Incorporating Categorical Variables in Normal Models and Further Modeling Issues

2009 ◽  
pp. 189-227
Keyword(s):  
Categorical Variables

Influence of General and Crystallized Intelligence on Vocabulary Test Performance

2002 ◽  
Vol 18 (1) ◽  
pp. 78-84 ◽  
Author(s):  
Eva Ullstadius ◽  
Jan-Eric Gustafsson ◽  
Berit Carlstedt
Keyword(s):  
Hierarchical Model ◽  
Test Performance ◽  
Verbal Ability ◽  
Testing Procedure ◽  
Intellectual Ability ◽  
Analysis Of Covariance ◽  
Categorical Variables ◽  
Vocabulary Test ◽  
Crystallized Intelligence ◽  
General Ability

Summary: Vocabulary tests, part of most test batteries of general intellectual ability, measure both verbal and general ability. Newly developed techniques for confirmatory factor analysis of dichotomous variables make it possible to analyze the influence of different abilities on the performance on each item. In the testing procedure of the Computerized Swedish Enlistment test battery, eight different subtests of a new vocabulary test were given randomly to subsamples of a representative sample of 18-year-old male conscripts (N = 9001). Three central dimensions of a hierarchical model of intellectual abilities, general (G), verbal (Gc'), and spatial ability (Gv') were estimated under different assumptions of the nature of the data. In addition to an ordinary analysis of covariance matrices, assuming linearity of relations, the item variables were treated as categorical variables in the Mplus program. All eight subtests fit the hierarchical model, and the items were found to load about equally on G and Gc'. The results also indicate that if nonlinearity is not taken into account, the G loadings for the easy items are underestimated. These items, moreover, appear to be better measures of G than the difficult ones. The practical utility of the outcome for item selection and the theoretical implications for the question of the origin of verbal ability are discussed.

An Alternative to Cohen's κ

2006 ◽  
Vol 11 (1) ◽  
pp. 12-24 ◽  
Author(s):  
Alexander von Eye
Keyword(s):  
Simulation Study ◽  
Null Hypothesis ◽  
Categorical Variables ◽  
Alternative Measure ◽  
Rater Agreement ◽  
Verbal Processing ◽  
Heavy Tailed ◽  
Applicant Selection

At the level of manifest categorical variables, a large number of coefficients and models for the examination of rater agreement has been proposed and used. The most popular of these is Cohen's κ. In this article, a new coefficient, κ s , is proposed as an alternative measure of rater agreement. Both κ and κ s allow researchers to determine whether agreement in groups of two or more raters is significantly beyond chance. Stouffer's z is used to test the null hypothesis that κ s = 0. The coefficient κ s allows one, in addition to evaluating rater agreement in a fashion parallel to κ, to (1) examine subsets of cells in agreement tables, (2) examine cells that indicate disagreement, (3) consider alternative chance models, (4) take covariates into account, and (5) compare independent samples. Results from a simulation study are reported, which suggest that (a) the four measures of rater agreement, Cohen's κ, Brennan and Prediger's κ n , raw agreement, and κ s are sensitive to the same data characteristics when evaluating rater agreement and (b) both the z-statistic for Cohen's κ and Stouffer's z for κ s are unimodally and symmetrically distributed, but slightly heavy-tailed. Examples use data from verbal processing and applicant selection.

Blood Management in Total Knee Arthroplasty: A Nationwide Analysis from 2011 to 2018

2020 ◽  
Author(s):  
Jared A. Warren ◽  
John P. McLaughlin ◽  
Robert M. Molloy ◽  
Carlos A. Higuera ◽  
Jonathan L. Schaffer ◽  
...  
Keyword(s):  
Total Knee Arthroplasty ◽  
Platelet Count ◽  
Knee Arthroplasty ◽  
Categorical Variables ◽  
Bleeding Disorders ◽  
Blood Management ◽  
Improvement Program ◽  
Preoperative Anemia ◽  
High Incidence ◽  
Total Knee

AbstractBoth advances in perioperative blood management, anesthesia, and surgical technique have improved transfusion rates following primary total knee arthroplasty (TKA), and have driven substantial change in preoperative blood ordering protocols. Therefore, blood management in TKA has seen substantial changes with the implementation of preoperative screening, patient optimization, and intra- and postoperative advances. Thus, the purpose of this study was to examine changes in blood management in primary TKA, a nationwide sample, to assess gaps and opportunities. The American College of Surgeons National Surgical Quality Improvement Program database was used to identify TKA (n = 337,160) cases from 2011 to 2018. The following variables examined, such as preoperative hematocrit (HCT), anemia (HCT <35.5% for females and <38.5% for males), platelet count, thrombocytopenia (platelet count < 150,000/µL), international normalized ration (INR), INR > 2.0, bleeding disorders, preoperative, and postoperative transfusions. Analysis of variances were used to examine changes in continuous variables, and Chi-squared tests were used for categorical variables. There was a substantial decrease in postoperative transfusions from high of 18.3% in 2011 to a low of 1.0% in 2018, (p < 0.001), as well as in preoperative anemia from a high of 13.3% in 2011 to a low of 9.5% in 2016 to 2017 (p < 0.001). There were statistically significant, but clinically irrelevant changes in the other variables examined. There was a HCT high of 41.2 in 2016 and a low of 40.4 in 2011 to 2012 (p < 0.001). There was platelet count high of 247,400 in 2018 and a low of 242,700 in 201 (p < 0.001). There was a high incidence of thrombocytopenia of 5.2% in 2017 and a low of low of 4.4% in 2018 (p < 0.001). There was a high INR of 1.037 in 2011 and a low of 1.021 in 2013 (p < 0.001). There was a high incidence of INR >2.0 of 1.0% in 2012 to 2015 and a low of 0.8% in 2016 to 2018 (p = 0.027). There was a high incidence of bleeding disorders of 2.9% in 2013 and a low of 1.8% in 2017 to 2018 (p < 0.001). There was a high incidence of preoperative transfusions of 0.1% in 2011 to 2014 and a low of <0.1% in 2015 to 2018 (p = 0.021). From 2011 to 2018, there has been substantial decreases in patients receiving postoperative transfusions after primary TKA. Similarly, although a decrease in patients with anemia was seen, there remains 1 out 10 patients with preoperative anemia, highlighting the opportunity to further improve and address this potentially modifiable risk factor before surgery. These findings may reflect changes during TKA patient selection, optimization, or management, and emphasizes the need to further advance multimodal approaches for perioperative blood management of TKA patients. This is a Level III study.

Bridging the Gap between Quantitative and Qualitative Historical Research: an application of multiple regression analysis and homogeneity analysis with alternating least squares

1996 ◽  
Vol 8 (3) ◽  
pp. 133-144 ◽  
Author(s):  
María del Mar del Pozo Andrés ◽  
Jacques F A Braster
Keyword(s):  
Least Squares ◽  
Multiple Regression ◽  
Historical Research ◽  
Alternating Least Squares ◽  
Categorical Variables ◽  
Two Dimensional ◽  
Homogeneity Analysis ◽  
Regression Approach ◽  
Dimensional Picture ◽  
Selection Of

In this article we propose two research techniques that can bridge the gap between quantitative and qualitative historical research. These are: (1) a multiple regression approach that gives information about general patterns between numerical variables and the selection of outliers for qualitative analysis; (2) a homogeneity analysis with alternating least squares that results in a two-dimensional picture in which the relationships between categorical variables are graphically presented.

Identifying Key Fraud Indicators in the Automobile Insurance Industry Using SQL Server Analysis Services

2019 ◽  
Vol 64 (2) ◽  
pp. 53-71
Author(s):  
Botond Benedek ◽  
Ede László
Keyword(s):  
Neural Network ◽  
Decision Tree ◽  
Naive Bayes ◽  
Insurance Industry ◽  
Naïve Bayes ◽  
Sql Server ◽  
Categorical Variables ◽  
Automobile Insurance ◽  
Price Determination ◽  
Mining Tool

Abstract Customer segmentation represents a true challenge in the automobile insurance industry, as datasets are large, multidimensional, unbalanced and it also requires a unique price determination based on the risk profile of the customer. Furthermore, the price determination of an insurance policy or the validity of the compensation claim, in most cases must be an instant decision. Therefore, the purpose of this research is to identify an easily usable data mining tool that is capable to identify key automobile insurance fraud indicators, facilitating the segmentation. In addition, the methods used by the tool, should be based primarily on numerical and categorical variables, as there is no well-functioning text mining tool for Central Eastern European languages. Hence, we decided on the SQL Server Analysis Services (SSAS) tool and to compare the performance of the decision tree, neural network and Naïve Bayes methods. The results suggest that decision tree and neural network are more suitable than Naïve Bayes, however the best conclusion can be drawn if we use the decision tree and neural network together.

Preoperative MRI findings and prediction of diagnostic utility of foramen ovale electrodes

2020 ◽  
Vol 132 (3) ◽  
pp. 692-699 ◽  
Author(s):  
Sarah K. Bick ◽  
Marjan S. Dolatshahi ◽  
Benjamin L. Grannan ◽  
Andrew J. Cole ◽  
Daniel B. Hoch ◽  
...  
Keyword(s):  
Minimally Invasive ◽  
Treatment Decision ◽  
Temporal Lobectomy ◽  
Categorical Variables ◽  
Continuous Variables ◽  
Foramen Ovale ◽  
Mri Findings ◽  
Noninvasive Methods ◽  
Diagnostic Modality ◽  
Diagnostic Investigations

OBJECTIVEForamen ovale electrodes (FOEs) are a minimally invasive method to localize mesial temporal seizures in cases in which noninvasive methods are inconclusive. The objective of this study was to identify factors predicting the ability of FOEs to yield a diagnosis in order to determine optimal candidates for this procedure.METHODSAll cases of diagnostic investigations performed with FOEs at the authors’ institution between 2005 and 2017 were reviewed. FOE investigation was defined as diagnostic if it led to a treatment decision. Demographic and clinical variables for diagnostic and nondiagnostic investigations were compared using a Wilcoxon rank-sum test for continuous variables and Fisher’s exact test for categorical variables.RESULTSNinety-three patients underwent investigations performed with FOEs during the study period and were included in the study. FOE investigation was diagnostic in 75.3% of cases. Of patients who underwent anterior temporal lobectomy following diagnostic FOE evaluation, 75.9% were Engel class I at last follow-up (average 40.1 months). When the diagnostic and nondiagnostic FOE groups were compared, patients who had diagnostic investigations were more likely to be male (57.1% male vs 26.1% in the nondiagnostic group, p = 0.015). They were also more likely to have temporal lesions on preoperative MRI (p = 0.018).CONCLUSIONSFOEs are a useful, minimally invasive diagnostic modality resulting in a treatment decision in 75% of cases. Male patients and patients with temporal lesions on MRI may be most likely to benefit from FOE investigation.

Comparing the efficacy of nebulized morphine with intravenous morphine in traumatic musculoskeletal pain management

2020 ◽  
Vol 8 (1) ◽  
pp. 21-21
Author(s):  
Mani Mofidi ◽  
Ali Dashti ◽  
Mahdi Rezai ◽  
Niloufar Ghodrati ◽  
Hoorolnesa Ameli ◽  
...  
Keyword(s):  
Pain Management ◽  
Pain Relief ◽  
Musculoskeletal Pain ◽  
Normal Saline ◽  
Rating Scale ◽  
Numerical Rating Scale ◽  
Vital Signs ◽  
Categorical Variables ◽  
Intravenous Morphine ◽  
Numerical Rating

Introduction: This study was designed to compare the effectiveness of intravenous morphine with nebulized morphine in pain relief of patients referring to the emergency setting with traumatic musculoskeletal pain. Methods: This randomized, placebo-controlled and double-blind clinical study evaluated 160 patients 18 to 65 years of age with acute traumatic pain, who attended the emergency department during 2019. Subjects were assessed with Numerical Rating Scale based on inclusion and exclusion criteria and randomly divided into two groups. In one group, 80 patients received IV morphine (0.1 mg/kg+5 mL normal saline) plus an equivalent volume of IV placebo. In the second group, 80 patients received nebulized morphine (0.2 mg/kg+5 mL normal saline) plus nebulized placebo. Pain score was monitored in all patients with Numerical Rating Scale before and after intervention at baseline, 15, 30, 45, and 60-minute intervals. Patients’ vital signs and possible adverse events were evaluated in each observation time points. Finally, all participants were assessed for their satisfaction with pain management. Data were analyzed using repeated measure analysis for continuous variables and Binomial test for categorical variables Results: There was no significant difference between the demographic characteristics of patients in study groups. Pain relief between the two groups was similar during the observation (0, 15, 30, 45, 60 min) (P>0.05). There were no changes in vital signs between two groups, although the nebulized group had lower systolic blood pressure at the time-point of 15 minutes after the treatment initiation (P=0.03). Conclusion: Although Nebulized morphine has similar efficacy in comparison with IV route, nebulization might be considered as the clinically efficacious route of morphine administration with minimal side effects, providing optimal pain relief in patients.

scholarly journals Patients’ Perceived Satisfaction Through Telephone-Assisted Tele-Consultation During the SARS-CoV-2 Pandemic Period: Observational Single-Centre Study at a Tertiary-Referral Colorectal Surgery Department

2021 ◽  
pp. 155335062110080
Author(s):  
Lara Blanco Terés ◽  
Carlos Cerdán Santacruz ◽  
Javier García Septiem ◽  
Rocío Maqueda González ◽  
José María Lopesino González ◽  
...  
Keyword(s):  
Categorical Variables ◽  
Average Score ◽  
Job Status ◽  
Perceived Satisfaction ◽  
The Future ◽  
Chi Squared ◽  
Single Centre Study ◽  
Set Up ◽  
Almost All ◽  
Surgery Department

Introduction: The pandemic produced by SARS-CoV-2 has obliged us to set up the tele-assistance to offer a continuity of care. This implies an innovation, being the degree of satisfaction of patients unknown. Methods: A telephonic survey was conducted with the validated in the Spanish tool Telehealth Usability Questionnaire (Telehealth Usability Questionnaire; rating from 1-7) of all candidate patients assisted consecutively in the Coloproctology Unit. We included demographic variables, education level, job status, diagnosis and consultation type. A descriptive study was done. The relationship between the willingness of consultation model in the future (telemedicine vs traditional) and the categorical variables was analysed through the chi-squared test. Results: A total of 115 patients were included. The average age was 59.9 years, being 60% women. The average score in each of the survey items was higher than 6 in all the questions but 1. 26.1% of the surveyed patients confessed being advocated to tele-assistance in the future. The only factors related to greater willingness to tele-assistance were male gender (37% vs 18.8%; P = .03) and a higher academic preparation level in favour of higher technical studies (35.9%) and university studies (32.4%) opposite to the rest ( P = .043). The rest of variables studied, job status, labour regimen, diagnostic group and consultation type did not show any relationship. Conclusions: A vast majority of patients answered favourably to almost all the items of the survey. However, only 26.1% of them would choose a model of tele-assistance without restrictions.

scholarly journals 288. Follow-Up Blood Cultures in Gram-Negative Bacteremia: How Do They Impact Outcomes

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S144-S144
Author(s):  
Azza Elamin ◽  
Faisal Khan ◽  
Ali Abunayla ◽  
Rajasekhar Jagarlamudi ◽  
aditee Dash
Keyword(s):  
Clinical Outcomes ◽  
Antibiotic Treatment ◽  
Readmission Rate ◽  
Blood Cultures ◽  
Categorical Variables ◽  
Gram Negative ◽  
Number Of Patients ◽  
Significant Difference ◽  
The Impact

Abstract Background As opposed to Staphylococcus. aureus bacteremia, there are no guidelines to recommend repeating blood cultures in Gram-negative bacilli bacteremia (GNB). Several studies have questioned the utility of follow-up blood cultures (FUBCs) in GNB, but the impact of this practice on clinical outcomes is not fully understood. Our aim was to study the practice of obtaining FUBCs in GNB at our institution and to assess it’s impact on clinical outcomes. Methods We conducted a retrospective, single-center study of adult patients, ≥ 18 years of age admitted with GNB between January 2017 and December 2018. We aimed to compare clinical outcomes in those with and without FUBCs. Data collected included demographics, comorbidities, presumed source of bacteremia and need for intensive care unit (ICU) admission. Presence of fever, hypotension /shock and white blood cell (WBC) count on the day of FUBC was recorded. The primary objective was to compare 30-day mortality between the two groups. Secondary objectives were to compare differences in 30-day readmission rate, hospital length of stay (LOS) and duration of antibiotic treatment. Mean and standard deviation were used for continuous variables, frequency and proportion were used for categorical variables. P-value &lt; 0.05 was defined as statistically significant. Results 482 patients were included, and of these, 321 (67%) had FUBCs. 96% of FUBCs were negative and 2.8% had persistent bacteremia. There was no significant difference in 30-day mortality between those with and without FUBCs (2.9% and 2.7% respectively), or in 30-day readmission rate (21.4% and 23.4% respectively). In patients with FUBCs compared to those without FUBCs, hospital LOS was longer (7 days vs 5 days, P &lt; 0.001), and mean duration of antibiotic treatment was longer (14 days vs 11 days, P &lt; 0.001). A higher number of patients with FUBCs needed ICU care compared to those without FUBCs (41.4% and 25.5% respectively, P &lt; 0.001) Microbiology of index blood culture in those with and without FUBCs Outcomes in those with and without FUBCs FUBCs characteristics Conclusion Obtaining FUBCs in GNB had no impact on 30-day mortality or 30-day readmission rate. It was associated with longer LOS and antibiotic duration. Our findings suggest that FUBCs in GNB are low yield and may not be recommended in all patients. Prospective studies are needed to further examine the utility of this practice in GNB. Disclosures All Authors: No reported disclosures

scholarly journals 49 A Quality Improvement Project to Assess and Refine the Handover Process at Morning Trauma Meetings

2021 ◽  
Vol 108 (Supplement_2) ◽  
Author(s):  
S Sadiq ◽  
M Tahir ◽  
I Nur ◽  
S Elerian ◽  
A Malik
Keyword(s):  
Categorical Variables ◽  
Next Of Kin ◽  
Chi Square ◽  
Neck Of Femur ◽  
Improvement Project ◽  
Handover Process ◽  
Neck Of Femur Fracture ◽  
The Impact ◽  
Standard Operating Protocol

Abstract Introduction Poor handover between shifts can result in patient harm. This study was designed to evaluate the impact of implementing a handover protocol on the quality of information exchanged in the trauma handover meetings in a UK hospital. Method A prospective single-centre observational study was performed at an NHS Trust. Ten consecutive weekday trauma meetings, involving 43 patients, were observed to identify poor practices in handover. This data was used in conjunction with the Royal College of Surgeons’ recommendations for effective handover (2007) to create and implement a standard operating protocol (SOP). Following its implementation, a further 8 consecutive meetings, involving a further 47 patients, were observed. The data was analysed using t-test for quantitative variables and chi-square or Fisher’s exact tests for categorical variables. Results An improvement was demonstrated in multiple aspects of trauma handover including past medical history, injury date, results, diagnosis, consent, mark, and starvation status (all p &lt; 0.001). Subgroup analyses showed that handover of neck-of-femur fracture patients including information on baseline mobility (p = 0.04), Nottingham-Hip-Fracture Score (p = 0.01), next-of-kin discussion (p = 0.075) and resuscitation status (p = 0.001) all improved following the intervention. Conclusions These results demonstrate that the implementation of a well-structured handover protocol can improve the transmission of critical information in trauma meetings.

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