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PubMedDate not supplied

Ion abundance criteria for gas chromatographic/mass spectrometric environmental analysis.

Mass and intensity calibration of gas chromatograph/mass spectrometer (GC/MS) responses is an important quality assurance issue for chemical analysis. Ion abundance calibration with decafluorotriphenylphosphine (DFTPP) was applied in 1975 to standardize quadrupole spectra to resemble the ion abundances that were obtainable from magnetic sector mass spectrometers. Modern quadrupole mass spectrometers provide significantly greater high-mass sensitivity than allowed under the 1975 study. Thus, those recommendations were reevaluated with 2 approaches. First, an interlaboratory study was conducted using 15 different gas chromatography/mass spectrometry (GC/MS) systems. Second, the U.S. Environmental Protection Agency Contract Laboratory Program (EPA-CLP) quality assurance data base was searched and over 6500 DFTPP tune results were plotted and evaluated. Based on these approaches, updated ion abundance criteria recommendations have been developed, which contemporary instruments can meet, and which meet data quality objectives regarding identification and quantitative analysis of analytes.

Chemical Phenomena↗
PubMed1994

Critical selection of toxicological data on chemicals. The example of the International Register of Potentially Toxic Chemicals data bank.

Although chemicals provide important benefits, they can also represent hazards to human health or the environment. However, due to number of chemicals involved, clearly no country can deal alone with the evaluation of existing scientific, technical and legal information on chemicals. This implies a need for countries to work together to assess the risk posed by chemicals and to share the results in a compatible and understandable way. In 1973 the governing council of United Nations Environment Programme (UNEP) decided to proceed with the creation of the International Register of Potentially Toxic Chemicals (IRPTC). The core activity of IRPTC is the collection of information on chemicals into a computerized data bank and the dissemination of these data in the form of chemical data profiles. The data profiles focus on selected chemicals with a potential to affect human health and the environment, excluding chemicals whose sole use is as a pharmaceutical or which are radioactive substances. The data collection and selection activities of IRPTC are driven by two key issues: data quality and data quantity. The objective of IRPTC in this respect is to provide decision-makers and other users with the most pertinent data available to substantiate their assessment of hazard. Providing reliable and detailed data in manageable amounts was the strategy chosen to achieve this objective.(ABSTRACT TRUNCATED AT 250 WORDS)

Databases, Factual↗
PubMed1994

Cancer incidence in atomic bomb survivors. Part II: Solid tumors, 1958-1987.

This report presents, for the first time, comprehensive data on the incidence of solid cancer and risk estimates for A-bomb survivors in the extended Life Span Study (LSS-E85) cohort. Among 79,972 individuals, 8613 first primary solid cancers were diagnosed between 1958 and 1987. As part of the standard registration process of the Hiroshima and Nagasaki tumor registries, cancer cases occurring among members of the LSS-E85 cohort were identified using a computer linkage system supplemented by manual searches. Special efforts were made to ensure complete case ascertainment, data quality and data consistency in the two cities. For all sites combined, 75% of the cancers were verified histologically, 6% were diagnosed by direct observation, 8% were based on a clinical diagnosis, and 12.6% were ascertained by death certificate only. A standard set of analyses was carried out for each of the organs and organ systems considered. Depending on the cancer site, Dosimetry System 1986 (DS86) organ or kerma doses were used for computing risk estimates. Analyses were based on a general excess relative risk model (the background rate times one plus the excess relative risk). Analyses carried out for each site involved fitting the background model with no dose effect, a linear dose-response model with no effect modifiers, a linear-quadratic dose-response model with no effect modifiers, and a series of linear dose-response models that included each of the covariates (sex, age at exposure, time since exposure, attained age and city) individually as effect modifiers. Because the tumor registries ascertain cancers in the registry catchment areas only, an adjustment was made for the effects of migration. In agreement with prior LSS findings, a statistically significant excess risk for all solid cancers was demonstrated [excess relative risk at 1 Sv (ERR1Sv) = 0.63; excess absolute risk (EAR) per 10(4) person-year sievert (PY Sv) = 29.7]. For cancers of the stomach (ERR1SV = 0.32), colon (ERR1SV = 0.72), lung (ERR1SV = 0.95), breast (ERR1SV = 1.59), ovary (ERR1SV = 0.99), urinary bladder (ERR1SV = 1.02) and thyroid (ERR1SV = 1.15), significant radiation associations were observed. There was some indication of an increase in tumors of the neural tissue (excluding the brain) among persons exposed to the bombs before age 20. For the first time, radiation has been associated with liver (ERR1SV = 0.49) and nonmelanoma skin (ERR1SV = 1.0) cancer incidence in the LSS cohort. The present analysis also strengthened earlier findings, based on a smaller number of cases, of an effect of A-bomb radiation on salivary gland cancer.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1995

Teleform scannable data entry: an efficient method to update a community-based medical record? Community care coordination network Database Group.

Community-based multi-disciplinary care of chronically ill individuals frequently requires the efforts of several agencies and organizations. The Community Care Coordination Network (CCCN) is an effort to establish a community-based clinical database and electronic communication system to facilitate the exchange of pertinent patient data among primary care, community-based and hospital-based providers. In developing a primary care based electronic record, a method is needed to update records from the field or remote sites and agencies and yet maintain data quality. Scannable data entry with fixed fields, optical character recognition and verification was compared to traditional keyboard data entry to determine the relative efficiency of each method in updating the CCCN database.

Chronic Disease↗
PubMed1997

Data mining issues for improved birth outcomes.

Issues obstructing progress in data mining for improved health outcomes include data quality problems, data redundancy, data inconsistency, repeated measures, temporal (time-contextual) measures, and data volume. Related issues involve theoretical and technical problems involving uncertainty management, missing data and missing values, and matching appropriate data mining techniques to patient data sets. Results of data mining research in progress are reported for Duke University's perinatal database that contains nearly a decade of clinical patient data, 71,753 database (patient) records and 4-5000 variables per patient.

Artificial Intelligence↗
PubMed2004

Serial correlation of quality control data--on the use of proper control charts.

BACKGROUND: Biochemical quality control (QC) data have been reported to be autocorrelated. Serial correlation may increase the rate of false alarms if the traditional exponentially weighted moving average (EWMA) control chart to monitoring the process mean is used. False alarms are the focus of this paper, where an alarm is defined as the occurrence of a QC value outside the three standard deviation control limits. METHODS: Daily QC measurements of common biochemical (Vitros 500) and hematological (SF-3000 and Behring Coagulation Timer (BCT)) quantities were recorded during several months while methods and analyzers showed no signs of malfunctioning. The time series were examined for autocorrelation and the performance of the EWMAST chart was compared with that of the EWMA chart when autocorrelation was present. RESULTS: Many of the time series showed significant signs of autocorrelation. Using the EWMA chart to monitor the process mean, false alarms were noted for positively autocorrelated time series, while this was seldom the case when the EWMAST chart was used. For some quantities, the EWMAST chart gave alarms. However, when the process autocorrelation and therefore the limits of the control chart were updated, the alarms given by the EWMAST chart were reduced or disappeared. In some cases the mean level changed over time, which is expected due to calibrations. This problem will be the topic of a subsequent paper. CONCLUSIONS: Positive autocorrelation may be present in QC data. In this case the EWMAST chart should be used in place of the EWMA chart.

Algorithms↗
PubMed2004

Sample size, power calculations, and their implications for the cost of thorough studies of drug induced QT interval prolongation.

Regulatory authorities require new drugs to be investigated using a so-called "thorough QT/QTc study" to identify compounds with a potential of influencing cardiac repolarization in man. Presently drafted regulatory consensus requires these studies to be powered for the statistical detection of QTc interval changes as small as 5 ms. Since this translates into a noticeable drug development burden, strategies need to be identified allowing the size and thus the cost of thorough QT/QTc studies to be minimized. This study investigated the influence of QT and RR interval data quality and the precision of heart rate correction on the sample sizes of thorough QT/QTc studies. In 57 healthy subjects (26 women, age range 19-42 years), a total of 4,195 drug-free digital electrocardiograms (ECG) were obtained (65-84 ECGs per subject). All ECG parameters were measured manually using the most accurate approach with reconciliation of measurement differences between different cardiologists and aligning the measurements of corresponding ECG patterns. From the data derived in this measurement process, seven different levels of QT/RR data quality were obtained, ranging from the simplest approach of measuring 3 beats in one ECG lead to the most exact approach. Each of these QT/RR data-sets was processed with eight different heart rate corrections ranging from Bazett and Fridericia corrections to the individual QT/RR regression modelling with optimization of QT/RR curvature. For each combination of data quality and heart rate correction, standard deviation of individual mean QTc values and mean of individual standard deviations of QTc values were calculated and used to derive the size of thorough QT/QTc studies with an 80% power to detect 5 ms QTc changes at the significance level of 0.05. Irrespective of data quality and heart rate corrections, the necessary sample sizes of studies based on between-subject comparisons (e.g., parallel studies) are very substantial requiring >140 subjects per group. However, the required study size may be substantially reduced in investigations based on within-subject comparisons (e.g., crossover studies or studies of several parallel groups each crossing over an active treatment with placebo). While simple measurement approaches with ad-hoc heart rate correction still lead to requirements of >150 subjects, the combination of best data quality with most accurate individualized heart rate correction decreases the variability of QTc measurements in each individual very substantially. In the data of this study, the average of standard deviations of QTc values calculated separately in each individual was only 5.2 ms. Such a variability in QTc data translates to only 18 subjects per study group (e.g., the size of a complete one-group crossover study) to detect 5 ms QTc change with an 80% power. Cost calculations show that by involving the most stringent ECG handling and measurement, the cost of a thorough QT/QTc study may be reduced to approximately 25%-30% of the cost imposed by the simple ECG reading (e.g., three complexes in one lead only).

Adult↗
PubMed1980

How to use malpractice data in quality assessment.

Although some may doubt that malpractice claims data are a useful quality assurance device, a recently released volume compiled by the National Association of Insurance Commissioners dispels much of this criticism, according to the author. The article details how the data were derived and suggests how they might be used in the hospital setting.

Data Collection↗
PubMedDate not supplied

Estimation of cancer incidences in Aichi prefecture: use of a model area with good quality registry data.

In Japan, local government is responsible for organization of population-based cancer registries and the quality of the registration remains modest, mainly due to dependence on voluntary-based operations without legal obligations. Aichi Prefecture cancer registry covers a large population, estimated at 7 million, and its quality has yet to reach the level required internationally. The derived cancer incidences for Aichi Prefecture therefore tend to be underestimated. In the present study we set up a model area, located in the central part of Aichi Prefecture, with a good quality of registry data, covering a reasonable population, including both urban and rural areas. Our model area has typical demographic features of Aichi Prefecture. The materials were data on cancer incidence and deaths during the period of 1996-2000 in this model area of Aichi prefecture, with a population of approximately one million, under the jurisdiction of three public health centers, covering nine municipalities. The percentage of death certificated notified (DCN) cases for all sites was around 14% and the incidence/death ratio was around 1.9. Estimated age-adjusted incidence rates were found to be 256.0 (per 100,000) for males and 177.6 for females, these values being 10-15 % higher than those generated using data for the whole prefecture, and quite close to incidence rates in Japan estimated from the highest quality of data available. It is suggested that the cancer incidence in the Aichi prefecture is indeed being underestimated and that the actual figures may be closer to the estimates provided here.

Adolescent↗
PubMed2002

North Philadelphia Health System employs handhelds to check data.

Quality control professionals typically do their work after patients have been seen and treated. But North Philadelphia Health System (NPHS) in Philadelphia, PA, is using wireless technology to collect and analyze data while the patient is still in the hospital, giving the quality control department the opportunity to improve care on the spot.

Computer Peripherals↗
PubMed2005

[Data supporting quality circle management of inpatient depression treatment].

BACKGROUND: Several quality assurance initiatives in health care have been undertaken during the past years. The next step consists of systematically combining single initiatives in order to built up a strategic quality management. METHODS: In a German multicenter study, the quality of inpatient depression treatment was measured in ten psychiatric hospitals. Half of the hospitals received comparative feedback on their individual results in comparison to the other hospitals (bench marking). Those bench markings were used by each hospital as a statistic basis for in-house quality work, to improve the quality of depression treatment. RESULTS: According to hospital differences concerning procedure and outcome, different goals were chosen. There were also differences with respect to structural characteristics, strategies, and outcome. The feedback from participants about data-based quality circles in general and the availability of bench-marking data was positive. The necessity of carefully choosing quality circle members and professional moderation became obvious. CONCLUSIONS: Data-based quality circles including bench-marking have proven to be useful for quality management in inpatient depression care.

Attitude of Health Personnel↗
PubMed2003

Assessment of uncertainty of NO2 measurements by the chemiluminescence method and discussion of the quality objective of the NO2 European Directive.

Hereafter, an assessment of the ability of the chemiluminescence method to measure ambient NO2 with an accuracy within 15%, as requested by the data quality objective of European directive 1999/30/CE, is presented. In general, uncertainty is evaluated using the response to reference materials or by means of inter-comparisons used to determine some statistics like repeatability, reproducibility and calibration bias. These are incomplete approaches and the method of the Guide to the Expression of Uncertainty in Measurement, advised by the Directive, should be preferred. In fact, even if it requires a large data set, it allows the relative influence of all possible sources of uncertainty to be studied. The extent of NO2 uncertainty is mainly dependent on the level of NO. It is decreased by NOx and the correlation between NOx and NO. Furthermore, the uncertainty budget reveals that the contribution of accuracy of calibration standard, linearity, converter efficiency and drift of the analyser between calibration checks to the overall uncertainty is less important than the contribution of interference, mainly humidity and PAN in rural areas. The relative expanded uncertainty of the NO2 hourly average exceeds 30% for NO2 concentrations lower than 40 microg m(-3). Nevertheless, the data quality objective of 15% is reached for 200 microg m(-3), the hourly limit value of the European directive. On the contrary, at the limit value on the annual average, 40 microg m(-3), the data quality objective is not met if NO is higher than 100 microg m(-3). However, the data quality objective could be reached by correcting the measurements with the bias due to interference.

Air Pollutants↗
PubMed2005

Interpreting drinking water quality in the distribution system using Dempster-Shafer theory of evidence.

Interpreting water quality data routinely generated for control and monitoring purposes in water distribution systems is a complicated task for utility managers. In fact, data for diverse water quality indicators (physico-chemical and microbiological) are generated at different times and at different locations in the distribution system. To simplify and improve the understanding and the interpretation of water quality, methodologies for aggregation and fusion of data must be developed. In this paper, the Dempster-Shafer theory also called theory of evidence is introduced as a potential methodology for interpreting water quality data. The conceptual basis of this methodology and the process for its implementation are presented by two applications. The first application deals with the interpretation of spatial water quality data fusion, while the second application deals with the development of water quality index based on key monitored indicators. Based on the obtained results, the authors discuss the potential contribution of theory of evidence as a decision-making tool for water quality management.

Data Interpretation, Statistical↗
PubMed2005

Use of audio-enhanced personal digital assistants for school-based data collection.

PURPOSE: To review the different data collection options available to school-based researchers and to present the preliminary findings on the use of audio-enhanced personal digital assistants (APDA) for use in school-based data collection. METHODS: A newly developed APDA system was used to collect baseline data from a sample of 645 seventh grade students enrolled in a school-based intervention study. Evaluative measures included student response, time to completion, and data quality (e.g., missingness, internal consistency of responses). Differences in data administration and data quality were examined among three groups of students: students newer to the United States speaking English as a second language; special education students; and students not newer to the United States receiving regular education. RESULTS: The APDA system was well received by students and was shown to offer improvements in data administration (increased portability, time to completion) and reduced missing data. Although time to completion and proportion of missing data were similar across the three groups of students, psychometric properties of the data varied considerably. CONCLUSIONS: The APDA system offers a promising new method for collecting data in the middle school environment. Students with cognitive deficits and language barriers were able to complete the survey in a similar amount of time without additional help; however, differences in data quality suggest that limitations in comprehension of the questions remained even though the questions were read to the respondents. More research on the use of APDA is necessary to fully understand the effect of data collection mode with special populations.

Adolescent↗
PubMed2003

Evaluation of a data collection tool (TELEform) for palliative care research.

INTRODUCTION: The Alberta Cancer Board Palliative Care Research Initiative (ACBPCRI) encourages province-wide collaboration on palliative care research projects. Because of geographic differences in information system infrastructure, it is necessary to evaluate and adopt a data collection tool that will span the variability in system hardware and software. We assessed TELEform (Cardiff Sofware Inc., Vista CA), an optical recognition-based technology that scans data collection paper forms and exports data to a computer database. We examined work place suitability, data quality, and effective resource utilization (time and cost) during the data collection tool evaluation. METHODS: Two hospices and two hospitals from the cities of Edmonton and Calgary participated in the revised Edmonton Staging System (rESS) project that used TELEform as its data collection tool. The evaluation was conducted over a period of 7 months. Data source such as e-mail and summary notes collected primarily through meetings and discussions with management, caregivers, researchers, and clerical staff was used to assess work practice and resource utilization. Descriptive statistics was employed to examine data quality and resource utilization. RESULTS: One hundred seventy eight patients were recruited during the 7-month trial. The costs and time involved in staff training, logistic support, and equipment startup were found to be reasonable. Data error and missing data were 0.4% and 0.6%, respectively. We initially encountered several problems with TELEform. The optical recognition tool could not easily pick up handwritten data. Furthermore, it was unforgiving in the sense that an error was not correctable by an eraser on the paper form. Data collectors found TELEform usage to be easy and simple because it retained the familiarity of paper-based recording. CONCLUSION: It is important to develop an information infrastructure to support research project data collection for different health settings across health regions. The TELEform based on optical recognition was able to respond to the need for current information processing. We believe that TELEform is a useful tool in terms of work practice, data quality, and resource utilization.

Data Collection↗
PubMed2002

Rapidly locating and characterizing pollutant releases in buildings.

Releases of airborne contaminants in or near a building can lead to significant human exposures unless prompt response measures are taken. However, possible responses can include conflicting strategies, such as shutting the ventilation system off versus running it in a purge mode or having occupants evacuate versus sheltering in place. The proper choice depends in part on knowing the source locations, the amounts released, and the likely future dispersion routes of the pollutants. We present an approach that estimates this information in real time. It applies Bayesian statistics to interpret measurements of airborne pollutant concentrations from multiple sensors placed in the building and computes best estimates and uncertainties of the release conditions. The algorithm is fast, capable of continuously updating the estimates as measurements stream in from sensors. We demonstrate the approach using a hypothetical pollutant release in a five-room building. Unknowns to the interpretation algorithm include location, duration, and strength of the source, and some building and weather conditions. Two sensor sampling plans and three levels of data quality are examined. Data interpretation in all examples is rapid; however, locating and characterizing the source with high probability depends on the amount and quality of data and the sampling plan.

Air Pollution, Indoor↗
PubMed1995

Multinational comparisons of stroke epidemiology. Evaluation of case ascertainment in the WHO MONICA Stroke Study. World Health Organization Monitoring Trends and Determinants in Cardiovascular Disease.

BACKGROUND AND PURPOSE: As part of the WHO MONICA Project (World Health Organization Monitoring Trends and Determinants in Cardiovascular Disease), mortality and incidence rates of acute stroke in 14 centers covering 21 populations from 11 countries were compared. METHODS: In this report, coverage and quality of the MONICA stroke registers were evaluated on five key indicators using data submitted to the MONICA Data Center. RESULTS: A low ratio of MONICA stroke register to routine statistics of stroke mortality and a low proportion of nonfatal out-of-hospital events were the most common biases; they indicate that identifications of fatal cases and/or case finding of nonfatal events occurring outside the hospital were inadequate in many MONICA centers. In 10 populations, the data quality analyses suggested that clarification of possible biases would be needed before these populations can be included in a comparative study. Data from the remaining 11 populations meet the data quality standards for multinational comparisons with respect to case ascertainment. CONCLUSIONS: These results show that multinational comparisons of stroke incidence involve considerable problems in developing and maintaining appropriate standards of data quality. However, after considerable efforts to ensure quality, comparisons of stroke data within the MONICA Project are possible among a large number of the MONICA populations. Our observations also indicate that results from multinational comparisons of stroke mortality based on routine statistics must be interpreted with caution.

Acute Disease↗