scholarly journals Latent-Class Methods to Evaluate Diagnostics Tests for Echinococcus Infections in Dogs

2013 ◽  
Vol 7 (2) ◽  
pp. e2068 ◽  
Author(s):  
Sonja Hartnack ◽  
Christine M. Budke ◽  
Philip S. Craig ◽  
Qiu Jiamin ◽  
Belgees Boufana ◽  
...  
Keyword(s):  
Latent Class ◽  
Latent Class Methods

scholarly journals Evaluating and optimizing the use of diagnostics during epidemics: Application to the 2017 plague outbreak in Madagascar

2021 ◽  
Author(s):  
Quirine Bosch ◽  
Voahangy Andrianaivoarimanana ◽  
Beza Ramasindrazana ◽  
Guillain Mikaty ◽  
Rado JL Rakotonanahary ◽  
...  
Keyword(s):  
Yersinia Pestis ◽  
Test Performance ◽  
Diagnostic Tests ◽  
Latent Class ◽  
Clinical Presentation ◽  
Analytical Framework ◽  
Rural Settings ◽  
Latent Class Methods ◽  
Diagnostic Outcomes ◽  
Case Classification

During outbreaks, the lack of diagnostic “gold standard” can mask the true burden of infection in the population and hamper the allocation of resources required for control. Here, we present an analytical framework to evaluate and optimize the use of diagnostics when multiple yet imperfect diagnostic tests are available. We apply it to laboratory results of 2,136 samples, analyzed with three diagnostic tests (based on up to seven diagnostic outcomes), collected during the 2017 pneumonic (PP) and bubonic plague (BP) outbreak in Madagascar, which was unprecedented both in the number of notified cases, clinical presentation, and spatial distribution. The extent of this outbreaks has however remained unclear due to non-optimal assays. Using latent class methods, we estimate that 7%-15% of notified cases were Yersinia pestis-infected. Overreporting was highest during the peak of the outbreak and lowest in the rural settings endemic to Yersinia pestis. Molecular biology methods offered the best compromise between sensitivity and specificity. The specificity of the rapid diagnostic test was relatively low (PP: 82%, BP: 85%), particularly for use in contexts with large quantities of misclassified cases. Comparison with data from a subsequent seasonal Yersinia pestis outbreak in 2018 reveal better test performance (BP: specificity 99%, sensitivity: 91%), indicating that factors related to the response to a large, explosive outbreak may well have affected test performance. We used our framework to optimize the case classification and derive consolidated epidemic trends. Our approach may help reduce uncertainties in other outbreaks where diagnostics are imperfect.

Cancer patients’ trade-offs for efficacy, toxicity, and cost.

2012 ◽  
Vol 30 (15_suppl) ◽  
pp. 6021-6021
Author(s):  
Yu-Ning Wong ◽  
Brian Egleston ◽  
Kush Sachdeva ◽  
Olivia Hamilton ◽  
Naa Eghan ◽  
...  
Keyword(s):  
Cancer Patients ◽  
Cost Sharing ◽  
Latent Class ◽  
Individual Characteristics ◽  
Health Plans ◽  
Trade Offs ◽  
Costly Treatment ◽  
College Educated ◽  
Latent Class Methods ◽  
Out Of Pocket Costs

6021 Background: When making treatment decisions, cancer patients (pts) must make trade-offs between efficacy, toxicity (tox) and cost. However, little is known about how individual characteristics influence these decisions, particularly as many face high out of pocket costs. Methods: We presented cancer pts with hypothetical scenarios that asked them to choose between 2 treatments of varying levels of efficacy, tox and cost. Each scenario included 9 choice pairs. Pts were given 2 of 3 scenarios described in the Table. Tox was also varied. Demographics, cost concerns and numeracy were assessed. Within each scenario, we used latent class methods to distinguish pt groups with discrete preferences. We then used regressions with group membership probabilities as covariates to identify associations. Results: We enrolled 400 pts. Median age was 61 years (range 27-90). 63% were female. 41% were college educated. 51% had an annual income ≥$60K. 25% were enrolled at a community hospital. 98% were insured. Within each of the 3 scenarios, we identified 3 pt classes with preferences for survival or aversion to high cost or toxicity. Across each of the scenarios, <6% of pts in the group averse to high cost chose the costlier treatment. >92% of pts in the group that favored survival chose the highest efficacy treatment. >65% of pts in the group with aversion to tox chose the lower tox treatment. Within each of the scenarios, pts in the group with preference for survival were more likely to have an income of >$60K (p<.05) and greater numeracy skills (p<.05). In scenarios 2 and 3, pts with concerns about treatment costs were more likely to be in the class that was averse to high cost (p<.05 for both). Conclusions: Even in hypothetical scenarios presented to insured pts, socioeconomic status was predictive of treatment choice. Higher income pts may be more likely to focus on survival when making decisions while those with greater cost concerns may be more likely to avoid costly treatment, regardless of survival or tox. This raises the possibility that health plans with greater cost-sharing may have the unintended consequence of increasing disparities in care. [Table: see text]

A comparison of the mixed logit and latent class methods for crash severity analysis

2014 ◽  
Vol 3-4 ◽  
pp. 11-27 ◽  
Author(s):  
Donald Mathew Cerwick ◽  
Konstantina Gkritza ◽  
Mohammad Saad Shaheed ◽  
Zachary Hans
Keyword(s):  
Latent Class ◽  
Mixed Logit ◽  
Crash Severity ◽  
Latent Class Methods

scholarly journals Identification of developmental trajectory classes: Comparing three latent class methods using simulated and real data

2019 ◽  
Vol 42 ◽  
pp. 100288 ◽  
Author(s):  
Jitske J. Sijbrandij ◽  
Tialda Hoekstra ◽  
Josué Almansa ◽  
Sijmen A. Reijneveld ◽  
Ute Bültmann
Keyword(s):  
Latent Class ◽  
Real Data ◽  
Developmental Trajectory ◽  
Latent Class Methods

Zur Anwendung der CES-D bei älteren Menschen: Dimensionsstruktur und Meßartefakte

Diagnostica ◽  
2000 ◽  
Vol 46 (1) ◽  
pp. 29-37 ◽  
Author(s):  
Herbert Matschinger ◽  
Astrid Schork ◽  
Steffi G. Riedel-Heller ◽  
Matthias C. Angermeyer
Keyword(s):  
Mental State ◽  
Latent Class ◽  
Mini Mental State Examination ◽  
Depression Scale ◽  
Epidemiological Studies ◽  
Partial Credit ◽  
Examination Score ◽  
State Examination

Zusammenfassung. Beim Einsatz der Center for Epidemiological Studies Depression Scale (CES-D) stellt sich das Problem der Dimensionalität des Instruments, dessen Lösung durch die Konfundierung eines Teilkonstruktes (“Wohlbefinden”) mit Besonderheiten der Itemformulierung Schwierigkeiten bereitet, da Antwortartefakte zu erwarten sind. Dimensionsstruktur und Eignung der CES-D zur Erfassung der Depression bei älteren Menschen wurden an einer Stichprobe von 663 über 75-jährigen Teilnehmern der “Leipziger Langzeitstudie in der Altenbevölkerung” untersucht. Da sich die Annahme der Gültigkeit eines partial-credit-Rasch-Modells sowohl für die Gesamtstichprobe als auch für eine Teilpopulation als zu restriktiv erwies, wurde ein 3- bzw. 4-Klassen-latent-class-Modell für geordnete Kategorien berechnet und die 4-Klassen-Lösung als den Daten angemessen interpretiert: Drei Klassen zeigten sich im Sinne des Konstrukts “Depression” geordnet, eine Klasse enthielt jene Respondenten, deren Antwortmuster auf ein Antwortartefakt hinwiesen. In dieser Befragtenklasse wird der Depressionsgrad offensichtlich überschätzt. Zusammenhänge mit Alter und Mini-Mental-State-Examination-Score werden dargestellt. Nach unseren Ergebnissen muß die CES-D in einer Altenbevölkerung mit Vorsicht eingesetzt werden, der Summenscore sollte nicht verwendet werden.

New Evidence on the Construct Validity of the ASI-3 and the Dimensional Conceptualization of Trait Anxiety Sensitivity From IRT Modeling

2017 ◽  
Vol 33 (3) ◽  
pp. 181-189 ◽  
Author(s):  
Christoph J. Kemper ◽  
Michael Hock
Keyword(s):  
Construct Validity ◽  
Anxiety Sensitivity ◽  
Latent Class ◽  
Dimensional Structure ◽  
Sensitivity Index ◽  
Response Scale ◽  
Established Risk Factor ◽  
Irt Models ◽  
Level Data ◽  
Extreme Response

Abstract. Anxiety Sensitivity (AS) denotes the tendency to fear anxiety-related sensations. Trait AS is an established risk factor for anxiety pathology. The Anxiety Sensitivity Index-3 (ASI-3) is a widely used measure of AS and its three most robust dimensions with well-established construct validity. At present, the dimensional conceptualization of AS, and thus, the construct validity of the ASI-3 is challenged. A latent class structure with two distinct and qualitatively different forms, an adaptive form (normative AS) and a maladaptive form (AS taxon, predisposing for anxiety pathology) was postulated. Item Response Theory (IRT) models were applied to item-level data of the ASI-3 in an attempt to replicate previous findings in a large nonclinical sample (N = 2,603) and to examine possible interpretations for the latent discontinuity observed. Two latent classes with a pattern of distinct responses to ASI-3 items were found. However, classes were indicative of participant’s differential use of the response scale (midpoint and extreme response style) rather than differing in AS content (adaptive and maladaptive AS forms). A dimensional structure of AS and the construct validity of the ASI-3 was supported.

The Solution Strategy as an Indicator of the Developmental Stage of Preschool Children’s Mental-Rotation Ability

2010 ◽  
Vol 31 (2) ◽  
pp. 95-100 ◽  
Author(s):  
Claudia Quaiser-Pohl ◽  
Anna M. Rohe ◽  
Tobias Amberger
Keyword(s):  
Preschool Children ◽  
Mental Rotation ◽  
Latent Class ◽  
Preschool Age ◽  
Stage Model ◽  
Solution Strategy ◽  
Thinking Aloud ◽  
Transition Analysis ◽  
Solution Strategies ◽  
Close Relationship

The solution strategies of preschool children solving mental-rotation tasks were analyzed in two studies. In the first study n = 111 preschool children had to demonstrate their solution strategy in the Picture Rotation Test (PRT) items by thinking aloud; seven different strategies were identified. In the second study these strategies were confirmed by latent class analysis (LCA) with the PRT data of n = 565 preschool children. In addition, a close relationship was found between the solution strategy and children’s age. Results point to a stage model for the development of mental-rotation ability as measured by the PRT, going from inappropriate strategies like guessing or comparing details, to semiappropriate approaches like choosing the stimulus with the smallest angle discrepancy, to a holistic or analytic strategy. A latent transition analysis (LTA) revealed that the ability to mentally rotate objects can be influenced by training in the preschool age.

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