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Statistical analysis of DNA sequencing data (1): accuracy test of DNA data by partial re-sequencing.

To qualify DNA data, we have developed a statistical method of deciding whether the DNA data has an acceptable accuracy in sequencing process. The method is to test the probability of sequencing errors, based on partial re-sequencing. The method was successfully applied to a yeast mitochondrial DNA which is previously sequenced (1). The analysis indicates that the entire sequence is very accurate although we found one base change error on the ND1 gene sequence data by a partial re-sampling. This method is applicable to any DNA data.

Chromosome Mapping↗

Accuracy of data in computer-based patient records.

Data in computer-based patient records (CPRs) have many uses beyond their primary role in patient care, including research and health-system management. Although the accuracy of CPR data directly affects these applications, there has been only sporadic interest in, and no previous review of, data accuracy in CPRs. This paper reviews the published studies of data accuracy in CPRs. These studies report highly variable levels of accuracy. This variability stems from differences in study design, in types of data studied, and in the CPRs themselves. These differences confound interpretation of this literature. We conclude that our knowledge of data accuracy in CPRs is not commensurate with its importance and further studies are needed. We propose methodological guidelines for studying accuracy that address shortcomings of the current literature. As CPR data are used increasingly for research, methods used in research databases to continuously monitor and improve accuracy should be applied to CPRs.

Algorithms↗

Accuracy of cervicovaginal fetal fibronectin test in predicting risk of spontaneous preterm birth: systematic review.

OBJECTIVE: To determine the accuracy with which a cervicovaginal fetal fibronectin test predicts spontaneous preterm birth in women with or without symptoms of preterm labour. DESIGN: Systematic quantitative review of studies of test accuracy. DATA SOURCES: Medline, Embase, PASCAL, Biosis, Cochrane Library, Medion, National Research Register, SCISEARCH, conference papers, manual searching of bibliographies of known primary and review articles, and contact with experts and manufacturer. STUDY SELECTION: Two reviewers independently selected and extracted data on study characteristics, quality, and accuracy. DATA EXTRACTION: Accuracy data were used to form 2x2 contingency tables with spontaneous preterm birth before 34 and 37 weeks' gestation and birth within 7-10 days of testing (for symptomatic pregnant women) as reference standards. Data were pooled to produce summary receiver operating characteristic curves and summary likelihood ratios for positive and negative test results. DATA SYNTHESIS: 64 primary articles were identified, consisting of 28 studies in asymptomatic women and 40 in symptomatic women, with a total of 26 876 women. Among asymptomatic women the best summary likelihood ratio for positive results was 4.01 (95% confidence interval 2.93 to 5.49) for predicting birth before 34 weeks' gestation, with corresponding summary likelihood ratio for negative results of 0.78 (0.72 to 0.84). Among symptomatic women the best summary likelihood ratio for positive results was 5.42 (4.36 to 6.74) for predicting birth within 7-10 days of testing, with corresponding ratio for negative results of 0.25 (0.20 to 0.31). CONCLUSION: Cervicovaginal fetal fibronectin test is most accurate in predicting spontaneous preterm birth within 7-10 days of testing among women with symptoms of threatened preterm birth before advanced cervical dilatation.

Biomarkers↗

HCFA's racial and ethnic data: current accuracy and recent improvements.

Using linked data from the Medicare Current Beneficiary Survey (MCBS), the authors assessed the accuracy of racial/ethnic classifications in HCFA's enrollment data base (EDB) before and after the 1997 effort to update the EDB. After the update, the sensitivity of the EDB was 97 percent for white persons and 95 percent for black persons, but less than 60 percent for all other categories. The positive predictive value was above 96 percent for white, black, and Hispanic persons, but below 80 percent for all others. There was some improvement in accuracy for white persons and black persons from 1991-1997, and larger improvements for the non-black minorities from 1996-1997.

Aged↗

Precision, accuracy, and data acceptance criteria in biopharmaceutical analysis.

Accuracy and precision are the most important criteria in the assessment of an analytical method, and monitoring quality control during sample analysis is essential to ensure the validity of reported results. Various approaches to testing accuracy, precision, and quality control were applied to 10 analytes from seven chromatographic bioanalytical methods. These methods include fixed interval bias and significance testing for accuracy; fixed interval percentage relative standard deviation (%RSD) and analysis of variance (ANOVA) approaches for precision; +/- 20% fixed range, 99% confidence interval, multiple rules, and range chart for individuals approaches for quality control acceptance criteria. Quality control approaches were also applied to the entire run and to a bracketed approach whereby results are considered valid only if bracketed by acceptable quality control. Accuracy and precision were assessed for six runs of each analyte at three concentrations established to represent the calibration range of the analytical method. Quality control acceptance criteria were evaluated using all data sets from each of the analytical methods collected during the course of running various numbers of real samples. The data suggest that the fixed interval bias criteria for accuracy was a more liberal method of accuracy assessment because three of the seven methods would have been rejected according to the significance testing criteria whereas all were acceptable by the fixed internal bias criteria. Precision can be effectively assessed for between- and within-run data by criteria set on unconfounded %RSD values or by separation of the sources of variation using an ANOVA approach applied to confounded data.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗

On the independence of modality effects and end-term and distance effects in episodic comparative judgement: dissociations of errors and reaction times.

The experiments reported in this paper explore the effect of modality variations on end-term and distance effects in an episodic comparative judgement task. In each experiment, subjects were to store serial orders of objects on a size dimension. Memory was tested after a brief retention interval by a comparative judgement task, in which subjects were presented with two elements of an order and had to point to the formerly larger one. Regarding the response times, we hypothesized that modality variations affect speed of stimulus identification and code access processes. We further hypothesized that distance variations and end-term variations affect processing components that are independent of the component affected by the modality variation. Finally, we assumed that end-term and distance effects interact in a predictable way, because they mirror competing response selection strategies. The latency data clearly support these hypotheses. As regards the accuracy data, we argued that modality and end-term effects, if they show up within the accuracy data, very likely have a different basis than the effects within the latency data. Again, the data support this assumption showing clear dissociations of accuracy and latency data. With respect to the stimulus modality variation, the whole data pattern shows that explanations which rely on modality-specific codings are not justifiable.

Adult↗

Receptor analysis: an arithmetic correction improves precision and accuracy.

Data of receptor analysis by ligand binding experiments should be processed using the formula DCORR = (B1 - B2.F1/F2)/VS.DCORR is an estimate of the concentration of receptor-bound radioligand; B1 and F1 are estimates of bound and free radioligand in assay 1; B2 and F2 are the corresponding values obtained from the parallel assay 2, which contains an additional excess of nonlabeled ligand; VS is the volume of assays 1 and 2 that was submitted to separation. DCORR will be superior to the conventional formula, D = (B1 - B2)/VS, if the radiolabeled receptor-ligand complexes are incompletely separated from nonspecifically bound and free radioligands. DCORR corrects for the systematic underestimation of the specifically bound radioligand implicated in D as well as for random errors due to imprecise pipetting during preparation of the parallel assays. The superiority of DCORR over D is verified by processing the data of androgen receptor analyses using agar gel electrophoresis for separation of bound and free radioligand.

Animals↗

Auditory and visual naming tests: normative and patient data for accuracy, response time, and tip-of-the-tongue.

Naming is typically assessed with visual naming tasks, yet, some patients with genuine word-finding difficulty (evident in auditorily based discourse) show minimal difficulty on such measures. Evidence from cortical mapping, brain imaging and neuropsychological studies suggests that auditory naming measures might provide more relevant or at least, complementary information. We developed comparable auditory and visual naming tests and present normative data for accuracy, response time, and tip-of-the-tongue responses based on 100 controls. Test validity was supported by findings that left temporal lobe epilepsy (TLE) patients (i.e., a population with expected naming difficulty) performed more poorly on auditory but not visual naming compared to right TLE patients (i.e., a population without expected naming difficulty). Internal and test-retest reliability coefficients were reasonable. Finally, test utility was assessed on an individual basis, and auditory but not visual naming performance predicted impairment.

Adult↗

Diagnostic accuracy and clinical utility of thermography for lumbar radiculopathy. A meta-analysis.

The role of thermography for diagnosing lumbar radiculopathy was evaluated by literature review and meta-analysis. From 81 relevant citations, 28 studies could be analyzed for diagnostic-accuracy data (sensitivity and specificity) and method. Diagnostic-accuracy data varied significantly between studies; therefore meaningful pooled summary statistics could not be reported. Twenty-seven studies had major methodologic flaws including biased test interpretations, faulty cohort assembly, poor clinical descriptions, and small sample size. The only study of reasonably high quality found no discriminant value for liquid-crystal thermography. The role of thermography remains unclear. Rigorous clinical research is required to establish its diagnostic accuracy and clinical utility. Thermography cannot be recommended currently for routine clinical use in evaluating low-back pain.

Back Pain↗

Training in data definitions improves quality of intensive care data.

BACKGROUND: Our aim was to assess the contribution of training in data definitions and data extraction guidelines to improving quality of data for use in intensive care scoring systems such as the Acute Physiology and Chronic Health Evaluation (APACHE) II and Simplified Acute Physiology Score (SAPS) II in the Dutch National Intensive Care Evaluation (NICE) registry. METHODS: Before and after attending a central training programme, a training group of 31 intensive care physicians from Dutch hospitals who were newly participating in the NICE registry extracted data from three sample patient records. The 5-hour training programme provided participants with guidelines for data extraction and strict data definitions. A control group of 10 intensive care physicians, who were trained according the to train-the-trainer principle at least 6 months before the study, extracted the data twice, without specific training in between. RESULTS: In the training group the mean percentage of accurate data increased significantly after training for all NICE variables (+7%, 95% confidence interval 5%-10%), for APACHE II variables (+6%, 95% confidence interval 4%-9%) and for SAPS II variables (+4%, 95% confidence interval 1%-6%). The percentage data error due to nonadherence to data definitions decreased by 3.5% after training. Deviations from 'gold standard' SAPS II scores and predicted mortalities decreased significantly after training. Data accuracy in the control group did not change between the two data extractions and was equal to post-training data accuracy in the training group. CONCLUSION: Training in data definitions and data extraction guidelines is an effective way to improve quality of intensive care scoring data.

APACHE↗

Benefit analysis of administrative and clinical computerization of a large transplant center.

PURPOSE: To evaluate the implementation of a computer system that fully integrates all activities of a transplant center and coordinates secure, live data across the continuum of care. METHODS: Our center implemented a comprehensive patient tracking solution customized at each point of patient entry. Benefits were measured by provider, patient, and staff feedback; time study; and retrospective cost analysis. RESULTS: Computerization of each patient file maintained current clinical information, which facilitated patient monitoring, expeditious evaluations and listings, marketing, automated correspondence, and regulatory reporting. Enhanced data have allowed for clinical analysis, which has improved outcomes. Data availability has promoted consistency in negotiations with commercial insurers to ensure profitability. Research capacity has been increased through standardized budgets, time study, and cost analysis and has facilitated patient recruitment. CONCLUSION: The need to integrate information is vital for data accuracy and integrity. Data integration has maximized performance, profitability, and accuracy while decreasing administrative time and costs.

Health Facility Administration↗

Improving the quality of data in your database: lessons from a cardiovascular center.

BACKGROUND: Creating and having a database should not be an end goal but rather a source of valid data and a means for generating information by which to assess process, performance, and outcome quality. The Cardiovascular Center at Shands Jacksonville (Florida) made measurable improvements in the quality of data in national registries and internally available software tools for collection of patient care data. METHODS: The process of data flow was mapped from source to report submission to identify input timing and process gaps, data sources, and responsible individuals. Cycles of change in data collection and entry were developed and the improvements were tracked. RESULTS: Data accuracy was improved by involving all caregivers in datasheet completion and assisting them with data-field definitions. Using hospital electronic databases decreased the need for manual retrospective review of medical records for datasheet completion. The number of fields with missing values decreased by 83.6%, and the number of missing values decreased from 31.2% to 1.9%. Data accuracy rose dramatically by realtime data entry at point of care. DISCUSSION: Key components to ensuring data quality for process and outcome improvement are (1) education of the caregiver team, (2) process supervision by a database manager, (3) commitment and explicit support from leadership,(4) increased and improved use of electronic data sources, and (5) data entry at point of care.

Cardiology↗

Ensuring high accuracy of data abstracted from patient charts: the use of a standardized medical record as a training tool.

BACKGROUND AND OBJECTIVE: The quality and integrity of information is pivotal to the validity and reliability of inferences drawn in research. The aim of this study is to demonstrate that standardized medical records can be used as a data abstraction training tool and a quality control measure to assess the validity of medical record data abstraction. METHODS: Sixteen hospitals participating in a large multicenter study completed standardized data abstraction forms for three representative patient charts, one in each of the clinical areas of postoperative critical care and trauma, cardiac surgery, and repair of hip fracture. The completed forms were then compared to an established gold standard. RESULTS: The mean level of accuracy of the completed data abstraction forms in each of the above three clinical areas were 91.8, 77.5, and 91.5%, respectively. Missing data accounted for 19% of all discrepancies between the abstracted information and the gold standard. If queries and amendments were made by the study's coordinating center, the mean level of accuracy increased to 94.5, 82.5, and 92.9%, respectively. CONCLUSION: The present study stressed the need for quality control measures in abstracting information from medical records to ensure the accuracy and completeness of the data abstracted.

Biomedical Research↗

Accuracy of radiographer plain radiograph reporting in clinical practice: a meta-analysis.

AIM: To determine the accuracy of radiographer plain radiograph reporting in clinical practice. MATERIALS AND METHODS: Studies were identified from electronic sources and by hand searching journals, personal communication and checking reference lists. Eligible studies assessed radiographers' plain radiograph reporting in clinical practice compared with a reference standard, and provided accuracy data to construct 2 x 2 contingency tables. Data were extracted on study eligibility and characteristics, quality and accuracy. Summary estimates of sensitivity and specificity and receiver operating characteristic curves were used to pool the accuracy data. RESULTS: Radiographers compared with a reference standard, report plain radiographs in clinical practice at 92.6% (95% CI: 92.0-93.2) and 97.7% (95% CI: 97.5-97.9) sensitivity and specificity, respectively. Studies that compared selectively trained radiographers and radiologists of varying seniority against a reference standard showed no evidence of a difference between radiographer and radiologist reporting accuracy of accident and emergency plain radiographs. Selectively trained radiographers were also found to report such radiographs as accurately as those not solely from accident and emergency, although some variation in reporting accuracy was found for different body areas. Training radiographers improved their accuracy when reporting normal radiographs. CONCLUSION: This study systematically synthesizes the literature to provide an evidence-base showing that radiographers can accurately report plain radiographs in clinical practice.

Clinical Competence↗

Accuracy of administrative data in trauma: splenic injuries as an example.

BACKGROUND: Accurate data are needed to evaluate clinical outcomes, therapeutic modalities, and quality of care in trauma. Administrative data, usually used for billing, have been used to evaluate performance and assess therapy in other medical specialties. This study was performed to determine whether administrative databases are accurate in the recording of information about trauma patients with splenic injuries. METHODS: Patients who had blunt splenic injuries were identified using a state trauma registry. The medical records of those patients were reviewed. The data collected by chart review were compared with data in the statewide administrative database of patients who had splenic injuries at the same four Level I and II trauma centers in the same 5-year period. Age, sex, admission date, and hospital were matched to assure comparison of the identical cohort. chi2 analysis was used to compare dichotomous data and Student's t test continuous data. RESULTS: The administrative database identified 641 and the trauma registry identified 529 patients with a diagnosis of splenic injury. A total of 401 patients were found in both databases. Of these, 120 (22.7%) patients were not recorded in the administrative database. Injury Severity Score was underreported by the administrative database (25.74 +/- 14.7 vs. 19.52 +/- 11, p < 0.0001). The administrative database underreported orthopedic, chest, and head injuries (317 vs. 215, 325 vs. 228, and 234 vs. 155, respectively; all p < 0.0001). Use of abdominal computed tomographic scan and diagnostic peritoneal lavage were also underreported (260 vs. 56 and 104 vs.17, both p < 0.0001). The number of operations on the spleen and number of orthopedic procedures were underreported (259 vs. 225, p < 0.014 and 147 vs. 94, p < 0.0001). Complications were markedly underreported by the administrative database (200 vs. 47, p < 0.0001) CONCLUSION: This study shows that administrative data lack accuracy in the recording of associated injuries, injury severity, diagnostics, procedures, and outcomes data in patients with splenic injuries. Whether these data should be used to evaluate treatment modalities or quality of care in trauma is questionable.

Adult↗

Comparison of different 3D navigation systems by a clinical "user".

Three-dimensional navigation systems are routinely used in endoscopic skull base surgery, neurosurgery, maxillo-facial and endoscopic sinus surgery. Their precision can, however, change in the course of one experiment. We have compared five different 3D navigation systems and discuss here possible reasons for the limits of system precision. A plexiglass cube on which test points were marked served as a test-model. Two well-trained system users measured the distances between the test points in each of the five systems. The results were compared with reference data provided by the NUMEREX device at the Technical University of Vienna. The accuracy data shown by all these 3D navigation systems ranged from 0.0 mm to 6.67 mm. The accuracy data of a system calculated in advance did not always correspond with the system precision on the screen. The system precision in the center of the cube was higher than on its surface, which made us conclude that the angle between the tracker system and the pointing device touching the test point may be critical for system precision. Applying an automatic registration step did not result in greater system precision. Slice thickness and the angle of the pointing device seem to be responsible for system precision.

Equipment Design↗

Does adding characters with missing data increase or decrease phylogenetic accuracy?

Missing data are a widely recognized nuisance factor in phylogenetic analyses, and the fear of missing data may deter systematists from including characters that are highly incomplete. In this paper, I used simulations to explore the consequences of including sets of characters that contain missing data. More specifically, I tested whether the benefits of increasing the number of characters outweigh the costs of adding missing data cells to a matrix. The results show that the addition of a set of characters with missing data is generally more likely to increase phylogenetic accuracy than decrease it, but the potential benefits of adding these characters quickly disappear as the proportion of missing data increases. Furthermore, despite the overall trend, adding characters with missing data does decrease accuracy in some cases. In these situations, the missing data entries are not themselves misleading, but their presence may mimic the effects of limited taxon sampling, which can positively mislead. Criteria are discussed for predicting whether adding characters with missing data may increase or decrease accuracy. The results of this study also suggest that accuracy can be increased to a surprising degree by (1) "filling the holes" in a data matrix as much as possible (even when relatively few taxa are missing data), and (2) adding fewer characters scored for all taxa rather than adding a larger number of characters known for fewer taxa. Missing data can also be eliminated from an analysis through the exclusion of incomplete taxa rather than incomplete characters, but this approach may reduce the usefulness of the analysis and (in some cases) the accuracy of the estimated trees.

Data Interpretation, Statistical↗