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Valid Methods (valid + methods)
Selected AbstractsEvaluating screening questionnaires using receiver Operating Characteristic (ROC) curves from two-phase (double) samplesINTERNATIONAL JOURNAL OF METHODS IN PSYCHIATRIC RESEARCH, Issue 3 2000Giulia Bisoffi Abstract The characteristics of psychiatric screening tests (for example, sensitivity, specificity, and AUC , the area under an ROC curve) are frequently assessed using data arising from two-phase samples. Too often, however, the statistical methods that are used are incorrect. They do not appropriately account for the sampling design. Valid methods for the estimate of sensitivity, specificity and, in particular, the AUC, together with its standard error, are discussed in detail and a Stata macro for the implementation of these methods is provided. Simple weighting procedures are used to correct for verification biases arising from the two-phase design, together with bootstrap or jackknife sampling for the calculation of valid standard errors. Copyright © 2000 Whurr Publishers Ltd. [source] A CRITICAL LOOK AT PAP ADEQUECY: ARE OUR CRITERIA SATISFACTORY?CYTOPATHOLOGY, Issue 2006D.R. Bolick Liquid based Pap (LBP) specimen adequacy is a highly documented, yet poorly understood cornerstone of our GYN cytology practice. Each day, as cytology professionals, we make adequacy assessments and seldom wonder how the criteria we use were established. Are the criteria appropriate? Are they safe? What is the scientific data that support them? Were they clinically and statistically tested or refined to achieve optimal patient care? In this presentation, we will take a fresh look at what we know about Pap specimen adequacy and challenge some of the core assumptions of our daily practice. LBP tests have a consistent, well-defined surface area for screening, facilitating the quantitative estimates of slide cellularity. This provides an unprecedented opportunity to establish reproducible adequacy standards that can be subjected to scientific scrutiny and rigorous statistical analysis. Capitalizing on this opportunity, the TBS2001 took the landmark step to define specimen adequacy quantitatively, and set the threshold for a satisfactory LBP at greater than 5,000 well visualized squamous epithelial cells. To date, few published studies have attempted to evaluate the validity or receiver operator characteristics for this threshold, define an optimal threshold for clinical utility or assess risks of detection failure in ,satisfactory' but relatively hypocellular Pap specimens. Five years of cumulative adequacy and cellularity data of prospectively collected Pap samples from the author's laboratory will be presented, which will serve as a foundation for a discussion on ,Pap failure'. A relationship between cellularity and detection of HSIL will be presented. Risk levels for Pap failure will be presented for Pap samples of different cellularities. The effect of different cellularity criterion on unsatisfactory Pap rates and Pap failure rates will be demonstrated. Results from this data set raise serious questions as to the safety of current TBS2001 adequacy guidelines and suggest that the risk of Pap failure in specimens with 5,000 to 20 000 squamous cells on the slide is significantly higher than those assumed by the current criteria. TBS2001 designated all LBP to have the same adequacy criterion. Up to this point, it has been assumed that ThinPrep, SurePath, or any other LBP would be sufficiently similar that they should have the same adequacy criteria. Data for squamous cellularity and other performance characteristics of ThinPrep and SurePath from the author's laboratory will be compared. Intriguing data involving the recently approved MonoPrep Pap Test will be reviewed. MonoPrep clinical trial data show the unexpected finding of a strong correlation between abundance of endocervical component and the detection of high-grade lesions, provoking an inquiry of a potential new role for a quantitative assessment of the transition zone component. The current science of LBP adequacy criteria is underdeveloped and does not appear to be founded on statistically valid methods. This condition calls us forward as a body of practitioners and scientists to rigorously explore, clarify and define the fundamental nature of cytology adequacy. As we forge this emerging science, we will improve diagnostic performance, guide the development of future technologies, and better serve the patients who give us their trust. Reference:, Birdsong GG: Pap smear adequacy: Is our understanding satisfactory? Diagn Cytopathol. 2001 Feb; 24(2): 79,81. [source] Measuring the social impacts of local authority events: a pilot study for a civic pride scaleINTERNATIONAL JOURNAL OF NONPROFIT & VOLUNTARY SECTOR MARKETING, Issue 3 2006Emma H. Wood The provision of events and festivals by local government has become an expected, if non-mandatory, service. In many regions these events are organised in order to provide mainly social, rather than economic, benefits to the community and, as a consequence, the providing organisation may have difficulty in demonstrating a return on the budget invested. This paper suggests the use of multi-item attitude scales to quantify the intangible effects of the festival or event programme on the local community. The findings of a pilot study of one such scale are presented showing that reliable and valid methods can be developed, that they can be relatively low cost and simple to apply and that the data generated can be of great value in enhancing the evaluation of local authority service provision. Copyright © 2006 John Wiley & Sons, Ltd. [source] A study of the criteria used by healthcare professionals, managers and patients to represent and evaluate quality careJOURNAL OF NURSING MANAGEMENT, Issue 2 2001M. Attree msc, bnurs Aim,To explore the perceptions of and criteria used by healthcare professionals, managers, patients and relatives to represent and evaluate their concept of quality care. Methods A qualitative approach using grounded theory was adopted in thisexploratory descriptive study. Data collected by semi-structured interviews from a purposive sample of nurses, doctors, managers (n = 36), patients (n = 34) and relatives (n = 7) from one acute medical ward, were subjected to content, question and thematic analysis, using an inductive categorizing scheme. Findings Three categories of criteria relating to Care Resources, Processes and Outcomes were identified by healthcare professionals, managers, patients and relatives. Resource criteria included Human Resources: staff numbers, ratio to patients, skill mix; as well as Environmental/Physical and Financial Resources. Process criteria included Care Functions, Practices and Standards as well as Interpersonal Processes. Outcome criteria were either patient-focused: feeling comfort, happy, informed and satisfied; or health-related: maintenance or progress with health problems and goals. Conclusions The criteria used by healthcare stakeholders in this study were notunusual; virtually all were supported by the literature, a proportion of which was evidence-based. The criteria identified in this study are however consensual, agreed upon by healthcare professionals, managers, patients and relatives as representing their view of quality care. These consensual criteria could be used as unifying constructs for the development and testing of more comprehensive, reliable and valid methods of evaluating quality care which represent its multiple dimensions and perspectives. [source] Development and Validation of the Child Psychosocial Distress Screener in BurundiAMERICAN JOURNAL OF ORTHOPSYCHIATRY, Issue 3 2008Mark J. D. Jordans MA In non-Western countries, efficient and contextually valid methods of community screening are scarce. The present study describes the validation of a new, brief, 7-item multi-informant screener for conflict-affected children (Child Psychosocial Distress Screener; CPDS). To determine concurrent validity, the CPSD was administered to 65 children and their teachers. CPDS scores were compared with indication for psychosocial treatment based on an in-depth clinical assessment by a psychiatrist and psychologist. Construct validity was assessed by testing the measurement equivalence of the CPDS in a community sample (N = 2,240) in Burundi. The CPDS identifies indication for treatment with an accurateness of .81(sensitivity of .84; specificity of .60). Test-retest reliability of the instrument is good (.83). A robust and invariant factor structure provides evidence for the construct validity of the CPSD. The CPDS appears to be a useful multidimensional tool that measures nonspecific child psychosocial distress, detecting children with an indication for treatment. Because of brevity and the ability to be administered by nonspecialists, the CPDS can be an appropriate instrument to screen large populations of conflict-affected children. [source] Early oral behaviour in preterm infants during breastfeeding: an electromyographic studyACTA PAEDIATRICA, Issue 6 2001K Hedberg Nyqvist The objectives were to increase the understanding of the characteristics of oral behaviour during breastfeeding in preterm infants and to validate direct observations of infant sucking. Twenty-six infants were investigated once by simultaneous observation and surface electromyography (EMG) at 32.1,37.1 postmenstrual weeks. The orbicularis oris muscle was used for data analysis, as it provided the most distinct registrations. High correlation coefficients were observed with respect to classifications of EMG data by two raters on the number of sucks per burst (r= 0.97) and duration of sucking bursts (r= 0.99). The agreement between direct observations of sucking and EMG data was high. The median for mean number of sucks per burst was 8 (range 2,33) and for longest burst 28 (5,96) sucks. Sucks with low and very high intensity constituted a median of 14 (1,94)% and 25 (0,87)% of all sucks. The range in mean sucking frequency was 1.0,1.8 sucks s- 1. Suck duration ranged from 0.6 to 1.1 s. There was a considerable variation between infants in the extent of mouthing. No association with maturational level appeared for any of the components in oral behaviour. Conclusion: EMG data provided evidence of early sucking competence in preterm infants during breastfeeding, with wide individual variations. Surface EMG and direct observation are recommended as valid methods in the evaluation of breastfeeding behaviour in preterm infants. [source] | ||||||||||