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PubMed2003

A certain art of uncertainty: case presentation and the development of professional identity.

Healthcare professionals use the genre of case presentation to communicate among themselves the salient patient information during treatment and management. In case presentation, many uncertainties surface, regarding, e.g., the reliability of patient reports, the sensitivity of laboratory tests, and the boundaries of scientific knowledge. The management and portrayal of uncertainty is a critical aspect of professional discourse. This paper documents the rhetorical features of certainty and uncertainty in novice case presentations, considering their pragmatic and problematic implications for students' professional socialization. This study was conducted during the third-year inpatient clerkship at a tertiary care, pediatric hospital in hospital in Canada. Data collection included: (1) non-participant observations of 19 student case presentations involving 11 student and 10 faculty participants, and (2) individual interviews with 11 students and 10 faculty participants. A grounded theory approach informed data collection and analysis. Five thematic categories emerged, two of which this paper considers in detail: "Thinking as a Student" and "Thinking as a Doctor". Within these categories, the management and portrayal of uncertainty was a recurrent issue. Teachers modeled central features of a "professional rhetoric of uncertainty", managing uncertainty of six origins: limits of individual knowledge, limits of evidence, limitless possibility, limits of patient's/parent's account, limits of professional agreement, and limits of scientific knowledge. By contrast, students demonstrated a "novice rhetoric of uncertainty", represented by their focus on responding to personal knowledge deficits through the strategies of acknowledgement, argument, and deflection. Some students moved towards the professional rhetoric of uncertainty, suggesting not only advances in communication, but also shifts in attitude towards patients and colleagues, that were interpreted as indications that this rhetoric shapes professional identity and interactions.

Attitude↗

PubMed2003

The relationship of pain, uncertainty, and hope in Taiwanese lung cancer patients.

The impact of cancer pain on the quality of life of lung cancer patients is obvious, but the relationship of cancer pain to uncertainty and level of hope in cancer patients is not clear and has been the subject of only a few studies. The purpose of this study is to look at the relationship of pain to uncertainty and hope in Taiwanese lung cancer patients. A cross-sectional and descriptive correlational design was used in this study. A convenience sample of lung cancer patients was recruited from chest medicine and oncology inpatient units at three teaching hospitals in the Taipei area of Taiwan. The research instruments included the Brief Pain Inventory-Chinese version (BPI-C), Mishel's Uncertainty Illness Scale (MUIS), and the Herth Hope Index (HHI). Data were analyzed using descriptive statistics, Pearson's correlation, and multiple regression. A total of 164 subjects were recruited, including 79 patients with cancer pain and 85 patients without cancer pain. The major findings were: 1) there were significant differences in level of uncertainty and level of hope between patients with cancer pain and those without. Patients with cancer pain reported higher levels of uncertainty and lower levels of hope than did patients without cancer pain; 2) pain severity was not significantly related to level of uncertainty; however, pain interference with daily life was positively correlated to level of uncertainty; 3) both pain severity and pain interference were negatively correlated with level of hope; and 4) after controlling for pain severity and pain interference, uncertainty was a significant predictor of level of hope. Important implications for future studies are discussed.

Cross-Sectional Studies↗

PubMed2004

Comparison of uncertainties related to standardization of urine samples with volume and creatinine concentration.

When measuring biomarkers in urine, volume (and time) or concentration of creatinine are both accepted methods of standardization for diuresis. Both types of standardization contribute uncertainty to the final result. The aim of the present paper was to compare the uncertainty introduced when using the two types of standardization on 24 h samples from healthy individuals. Estimates of uncertainties were based on results from the literature supplemented with data from our own studies. Only the difference in uncertainty related to the two standardization methods was evaluated. It was found that the uncertainty associated with creatinine standardization (19-35%) was higher than the uncertainty related to volume standardization (up to 10%, when not correcting for deviations from 24 h) for 24 h urine samples. However, volume standardization introduced an average bias of 4% due to missed volumes in population studies. When studying a single 24 h sample from one individual, there was a 15-20% risk that the sample was incomplete. In this case a bias of approximately 25% was introduced when using volume standardization, whereas the uncertainty related to creatinine standardization was independent of the completeness of the sample. The uncertainty of creatinine standardization is increased when studying single voids rather than 24 h urine samples. This is partially counteracted by the increased statistical power due to the increased number of samples for each individual. Furthermore, there is a considerable increase in convenience for the participants, when collecting small volumes rather than complete 24 h samples.

Adult↗

PubMed2006

Accounting for uncertainty in marine reserve design.

Ecosystems and the species and communities within them are highly complex systems that defy predictions with any degree of certainty. Managing and conserving these systems in the face of uncertainty remains a daunting challenge, particularly with respect to developing networks of marine reserves. Here we review several modelling frameworks that explicitly acknowledge and incorporate uncertainty, and then use these methods to evaluate reserve spacing rules given increasing levels of uncertainty about larval dispersal distances. Our approach finds similar spacing rules as have been proposed elsewhere - roughly 20-200 km - but highlights several advantages provided by uncertainty modelling over more traditional approaches to developing these estimates. In particular, we argue that uncertainty modelling can allow for (1) an evaluation of the risk associated with any decision based on the assumed uncertainty; (2) a method for quantifying the costs and benefits of reducing uncertainty; and (3) a useful tool for communicating to stakeholders the challenges in managing highly uncertain systems. We also argue that incorporating rather than avoiding uncertainty will increase the chances of successfully achieving conservation and management goals.

Conservation of Natural Resources↗

PubMed2004

Uncertainty and its antecedents in patients with atrial fibrillation.

The aim of this descriptive, correlational, and cross-sectional survey was to explore uncertainty in patients with atrial fibrillation and to examine the relationships between uncertainty and its antecedents, including education, social support, and perceived seriousness of illness in patients newly diagnosed with atrial fibrillation. The theoretical framework of the study was Mishel's middle-range nursing theory of uncertainty in illness. A convenience sample of 81 participants recruited from two academic medical centers over 10 months was interviewed. Uncertainty was moderately high in patients with atrial fibrillation compared to other clinical populations. Among antecedents of uncertainty, higher education was significantly associated with less uncertainty (beta = -.21 to -.25). Except for tangible support, persons with greater social supports perceived less uncertainty (beta= -.25 to -.27), and individuals with greater perceived seriousness of illness reported greater uncertainty (beta= .30 to .33).

Academic Medical Centers↗

PubMed2004

[The relationship of uncertainty, hope and quality of life in patients with breast cancer].

PURPOSE: The purpose of this study was to explore the relationship of uncertainty, hope and quality of life in patients with breast cancer. METHOD: The subjects of the study were 113 breast cancer patients treated at 3 university hospitals in Daegu and Busan from June 1 to September 30, 2003. Uncertainty was measured by the Mishel Uncertainty in Illness Scale (MUIS), Hope was measured by Nowotny's Hope Scale, and quality of life by Ro's Korean Quality of Life(QOL). Data was analyzed with the SPSS program by t-test, ANOVA, Spearman's rank correlation and Multiple Regression Analysis. RESULT: The scores of uncertainty were negatively correlated with hope and QOL(all p's<0.05). Uncertainty revealed that there was a negative correlation among subitems of hope such as confidence, relationship with others, possibility of future, and inner motivation(r=-.333, p=.000; r=-.230, p=.015; r=-.260, p=.006; r=-.291, p=.003). Uncertainty also showed a negative correlation among subitems of QOL such as emotional status, self esteem, and relationship with family(r=-.29, p=.004; r=-.326, p=.000; r=-.197, p=.044), whereas hope revealed a positive correlation among subitems of QOL such as emotional status, self esteem, relationship with neighbor, and relationship with family(r=.243, p=.011; r=.487, p=.000; r=.29, p=.001; r=.29, p=.001). The score of uncertainty was low in graduate school students and subjects using problem solving as a coping method. However, the score of hope was high in college students and subjects using a problem solving method, and the score of QOL was high in professionals. CONCLUSION: Based on the study results, breast cancer patients experienced living with uncertainty and maintaining hope. Thus the study's findings can be useful in directing a comprehensive nursing care plan to improve QOL of breast cancer patients.

Adult↗

PubMed2005

Informational needs, health locus of control and uncertainty among women hospitalized with gynecological diseases.

BACKGROUND: Only a few studies on perceptions of uncertainty in illness have provided empirical evidence for the relationships of informational needs and the health locus of control with uncertainty among hospitalized women with gynecological diseases. The purpose of this study was to test Mishel's Theory of Uncertainty in Illness (1990) among women hospitalized with gynecological diseases. METHODS: Taiwan. The convenience sample consisted of 81 hospitalized women with gynecological diseases, who were invited to complete a set of self-administered questionnaires prior to receiving any treatment. Path analysis was used to determine the relationships of informational needs and the health locus of control with uncertainty. RESULTS: The study findings suggested that hospitalized women's information needs are substantial, and they reported lower levels of uncertainty during hospitalization. Women's experience of uncertainty may be elevated by decreasing the informational needs as moderated by the beliefs that their health outcomes are under the control of chance. Three predictors in this model, i.e., informational needs moderated by the interaction of chance control, years of education, and number of treatments explained 30% of the variance of uncertainty of hospitalized women with gynecological diseases. CONCLUSIONS: The study findings suggest that healthcare professionals should carefully assess uncertainty levels among female patients with lower education and who believed that their health status depends upon external forces such as fate, luck, or chance.

Adolescent↗

PubMed1996

Evolution of science-based uncertainty factors in noncancer risk assessment.

The science behind the use of uncertainty factors has progressed considerably. Increased knowledge of inter- and intraspecies sensitivity, mechanisms of action, and detailed evaluation of data bases can support the use of data-derived uncertainty factors, which ultimately results in a risk assessment with greater confidence. Papers that highlight available data for each of several areas of uncertainty are discussed, indicating that choice of the appropriate factor requires scientific judgement on a case-by-case basis. Case studies from EPA and Health Canada risk values illustrate the use of data in chemical specific risk assessments to support the selection of uncertainty factors other than the default value of 10-fold. In the case studies, the types of data that have been used to support a change in the default value are explicitly reviewed, as well as why the data support a different uncertainty factor, how the uncertainty was reduced, and what assumptions have been satisfied or replaced. Incorporation of all available scientific data into the risk assessment process fosters increased research and ultimately reduces uncertainty. The results of this review support the use of data-derived uncertainty factors when appropriate scientific data are available.

Animals↗

PubMedDate not supplied

Does physician uncertainty affect patient satisfaction?

Physicians may choose one of several strategies when initially uncertain about making a specific therapeutic recommendation. The authors investigated how patients' satisfaction is affected by disclosure of uncertainty and its attempted resolution during a clinical encounter. Three hundred and four patients awaiting appointments at a university hospital's ambulatory medical clinic were randomized to view one of five videotapes (VTs) of a patient seeking advice about antimicrobial prophylaxis for a heart murmur. In VT-1 and VT-2, the physician disclosed no uncertainty and prescribed therapy. In VT-3, VT-4, and VT-5, the physician openly conveyed uncertainty but then: (VT-3) prescribed antibiotics without resolving his uncertainty; (VT-4) consulted a reference book with the patient present, then prescribed; or (VT-5) checked a computer with the patient present, then prescribed. Patients rated their satisfaction with the physician on a standardized questionnaire. Differences in satisfaction between the five VTs were significant (p = 0.001), with the highest ratings found for VT-1 and VT-2, where no uncertainty was disclosed. The lowest ratings in satisfaction were found when the physician expressed but then ignored uncertainty (VT-3) or examined a textbook (VT-4). Global satisfaction was inversely and significantly correlated (r = -0.47) with the patients' perception of uncertainty in the physician. The manner in which clinical uncertainty is disclosed to patients and then resolved by the physician appears to affect patients' satisfaction.

Ambulatory Care↗

PubMed2001

The effects of radiotherapy treatment uncertainties on the delivered dose distribution and tumour control probability.

Uncertainty in the precise quantity of radiation dose delivered to tumours in external beam radiotherapy is present due to many factors, and can result in either spatially uniform (Gaussian) or spatially non-uniform dose errors. These dose errors are incorporated into the calculation of tumour control probability (TCP) and produce a distribution of possible TCP values over a population. We also study the effect of inter-patient cell sensitivity heterogeneity on the population distribution of patient TCPs. This study aims to investigate the relative importance of these three uncertainties (spatially uniform dose uncertainty, spatially non-uniform dose uncertainty, and inter-patient cell sensitivity heterogeneity) on the delivered dose and TCP distribution following a typical course of fractionated external beam radiotherapy. The dose distributions used for patient treatments are modelled in one dimension. Geometric positioning uncertainties during and before treatment are considered as shifts of a pre-calculated dose distribution. Following the simulation of a population of patients, distributions of dose across the patient population are used to calculate mean treatment dose, standard deviation in mean treatment dose, mean TCP, standard deviation in TCP, and TCP mode. These parameters are calculated with each of the three uncertainties included separately. The calculations show that the dose errors in the tumour volume are dominated by the spatially uniform component of dose uncertainty. This could be related to machine specific parameters, such as linear accelerator calibration. TCP calculation is affected dramatically by inter-patient variation in the cell sensitivity and to a lesser extent by the spatially uniform dose errors. The positioning errors with the 1.5 cm margins used cause dose uncertainty outside the tumour volume and have a small effect on mean treatment dose (in the tumour volume) and tumour control.

Humans↗

PubMed1995

Perceived uncertainty about menopause in women attending an educational program.

The purpose of this study was to identify predictors of uncertainty among a convenience sample of 177 women attending an educational program on menopause and to determine whether an educational intervention modified uncertainty. A one group pre-test post-test was used. Uncertainty, measured by the Mishel Uncertainty in Illness Scale-Community Form (MUIS-C), was relatively high before, and decreased significantly after, the program. Findings indicated that uncertainty is an important phenomenon associated with menopause. Predictors of pre-program uncertainty (T1) were age and perceived level of knowledge. Post-program uncertainty (T2) was predicted by pre-program uncertainty (T1), perceived knowledge gained and level of knowledge at (T2).

Adult↗

PubMed2005

[Radiotherapy for breast cancer: respiratory and set-up uncertainties].

Adjuvant Radiotherapy has been shown to significantly reduce locoregional recurrence but this advantage is associated with increased cardiovascular and pulmonary morbidities. All uncertainties inherent to conformal radiation therapy must be identified in order to increase the precision of treatment; misestimation of these uncertainties increases the potential risk of geometrical misses with, as a consequence, underdosage of the tumor and/or overdosage of healthy tissues. Geometric uncertainties due to respiratory movements or set-up errors are well known. Two strategies have been proposed to limit their effect: quantification of these uncertainties, which are then taken into account in the final calculation of safety margins and/or reduction of respiratory and set-up uncertainties by an efficient immobilization or gating systems. Measured on portal films with two tangential fields, CLD (central lung distance), defined as the distance between the deep field edge and the interior chest wall at the central axis, seems to be the best predictor of set-up uncertainties. Using CLD, estimated mean set-up errors from the literature are 3.8 and 3.2 mm for the systematic and random errors respectively. These depend partly on the type of immobilization device and could be reduced by the use of portal imaging systems. Furthermore, breast is mobile during respiration with motion amplitude as high as 0.8 to 10 mm in the anteroposterior direction. Respiratory gating techniques, currently on evaluation, have the potential to reduce effect of these movements. Each radiotherapy department should perform its own assessments and determine the geometric uncertainties with respect of the equipment used and its particular treatment practices. This paper is a review of the main geometric uncertainties in breast treatment, due to respiration and set-up, and solutions proposed to limit their impact.

Breast Neoplasms↗

PubMed2007

Estimating the uncertainty associated with Widmark's equation as commonly applied in forensic toxicology.

No computation is performed more frequently by forensic toxicologists than that involving Widmark's equation. The equation is employed to estimate either the number of drinks consumed or the corresponding blood or breath alcohol concentration. Despite the wide use of Widmark's equation, rarely is an uncertainty estimate also provided. Estimates from Widmark's equation involve at least seven uncertain random variables. Uncertainty estimates are presented that rely on methods of general error propagation compared to a method developed by Widmark. Assuming reasonable variable and uncertainty estimates, the error propagation method yielded for N=10.4 drinks, a combined uncertainty (standard deviation) of 1.3 drinks (CV=12.3%). Similarly, estimating the blood alcohol concentration yielded for 0.120 g/100 ml, an uncertainty of 0.0255 g/100 ml (CV=21.2%). Widmark's uncertainty method yielded 1.6 drinks (CV=15.4%). The derivation of Widmark's uncertainty estimate is also presented, showing that he considered only rho and beta to be uncertain. Widmark estimates for the number of drinks should include a 2CV estimate of approximately 25% while the blood alcohol concentration estimate should include a 2CV estimate of approximately 42%. Including valid estimates of uncertainty should enhance the legal admissibility and confidence for Widmark estimations.

Alcohol Drinking↗

PubMed2000

Experimental manipulation of intolerance of uncertainty: a study of a theoretical model of worry.

Intolerance of uncertainty has been identified as an important variable related to worry and Generalized Anxiety Disorder (GAD) [Dugas, M. J., Gagnon, F., Ladouceur, R., & Freeston, M. H. (1998). Generalized anxiety disorder: a preliminary test of a conceptual model. Behaviour Research and Therapy, 36, 215-226; Ladouceur, R., Dugas, M. J., Freeston, M. H., Rhéaume, J., Blais, F., Boisvert, J.-M., Gagnon, F., & Thibodeau, N. (1999). Specificity of Generalized Anxiety Disorder symptoms and processes. Behavior Therapy, 30, 197-207]. The goal of the present study was to clarify the relationship between this cognitive process and worry by experimentally manipulating intolerance of uncertainty. A gambling procedure was used to increase intolerance of uncertainty in one group (N = 21) and to decrease intolerance of uncertainty in another group (N = 21). The results indicate that participants whose level of intolerance of uncertainty was increased showed a higher level of worry, compared to participants whose level of intolerance of uncertainty was decreased. These results provide some initial clarifications as to the causal nature of the link between intolerance of uncertainty and worry. These results are coherent with our theoretical model of worry and GAD (Dugas et al., 1998), which stipulates that intolerance of uncertainty plays a key role in the acquisition and maintenance of excessive worry.

Adolescent↗

PubMed2003

Forward and backward uncertainty propagation: an oxidation ditch modelling example.

In the field of water technology, forward uncertainty propagation is frequently used, whereas backward uncertainty propagation is rarely used. In forward uncertainty analysis, one moves from a given (or assumed) parameter subspace towards the corresponding distribution of the output or objective function. However, in the backward uncertainty propagation, one moves in the reverse direction, from the distribution function towards the parameter subspace. Backward uncertainty propagation, which is a generalisation of parameter estimation error analysis, gives information essential for designing experimental or monitoring programmes, and for tighter bounding of parameter uncertainty intervals. The procedure of carrying out backward uncertainty propagation is illustrated in this technical note by working example for an oxidation ditch wastewater treatment plant. Results obtained have demonstrated that essential information can be achieved by carrying out backward uncertainty propagation analysis.

Forecasting↗

PubMed1999

Uncertainty quantification in the health consequences of the boiling liquid expanding vapour explosion phenomenon.

A methodology for estimating the risk owing to the phenomenon of boiling liquid expanding vapour explosion (BLEVE) in the presence of uncertainties both in the model and in the parameters of the models is presented. BLEVE takes place when a tank containing liquefied petroleum gas (LPG) is exposed to fire and fails catastrophically. Two models have been used in the estimation of the intensity of thermal radiation from the resulting fireball, namely the solid-flame model assuming an emission power independent of the combustion mass and the point-source model that estimates the emissive power as a function of the combustion mass. Three measures of the BLEVE consequences, the intensity of thermal radiation, the dose of thermal radiation and the probability of loss of life as a result of the exposure to the thermal radiation and as a function of the distance from the center of the tank have been considered. Uncertainties in the exact values of the parameters of the models have been quantified and the resulting uncertainties in the three consequence measures have been assessed. A sensitivity analysis on the relative contribution of the uncertainty in each of the input variables to the uncertainties of the consequence measures has been performed. One conclusion is that the uncertainties in the probability of loss of life are mainly due to the uncertainties in the model of the physical phenomenon rather than to the uncertainties of the dose-response model.

Accidents, Occupational↗

PubMed2005

Uncertainties in scaling factors for ab initio vibrational frequencies.

Vibrational frequencies determined from ab initio calculations are often scaled by empirical factors. An empirical scaling factor partially compensates for the errors arising from vibrational anharmonicity and incomplete treatment of electron correlation. These errors are not random but are systematic biases. We report scaling factors for 40 combinations of theory and basis set, intended for predicting the fundamental frequencies from computed harmonic frequencies. An empirical scaling factor carries uncertainty. We quantify and report, for the first time, the uncertainties associated with the scaling factors. The uncertainties are larger than generally acknowledged; the scaling factors have only two significant digits. For example, the scaling factor for HF/6-31G(d) is 0.8982 +/- 0.0230 (standard uncertainty). The uncertainties in the scaling factors lead to corresponding uncertainties in predicted vibrational frequencies. The proposed method for quantifying the uncertainties associated with scaling factors is based on the Guide to the Expression of Uncertainty in Measurement, published by the International Organization for Standardization (ISO). The data used are from the Computational Chemistry Comparison and Benchmark Database (CCCBDB), maintained by the National Institute of Standards and Technology, which includes more than 3939 independent vibrations for 358 molecules.

Journal Article↗

PubMed2001

Response surface modelling and kinetic studies for the experimental estimation of measurement uncertainty in derivatisation.

Response surface modelling is proposed as an approach to the estimation of uncertainties associated with derivatisation, and is compared with a kinetic study. Fatty acid methyl ester formation is used to illustrate the approach, and kinetic data for acid-catalysed methylation and base-catalysed transesterification are presented. Kinetic effects did not lead to significant uncertainty contributions under normal conditions for base-catalysed transesterification of triglycerides. Uncertainties for acid-catalysed methylation with BF3 approach significance, but could be reduced by extending reaction times from 3 to 5 min. Non-linearity is a common feature of response surface models for derivatisation and compromised first-order estimates of uncertainty; it was necessary to include higher order differential terms in the uncertainty estimate. Simulations were used to examine the general applicability of the approach and to study the effects of poor precision and of change of response surface model. It is concluded that reliable uncertainty estimates are available only when the model is statistically significant, robust, representative of the underlying behaviour of the system, and forms a good fit to the data; arbitrary models are not generally suitable for uncertainty estimation. Where statistically insignificant effects were included in models, they gave negligible uncertainty contributions.

Journal Article↗