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PubMed1976

Development of long-term care data systems. 20. Problems of data collection in long-term health care.

Data collection involves decisions of what to count, how to count, and what to do with the count. The first of these will be determined by the third, since it is the goals which decide what data should be collected. Ways of categorizing and classifying patients, services, treatments, and personnel in relation to long-term medical care must be formulated, and development of comparable data requires definition of baselines or units of observation. Many decision makers with widely varying interests will be competing for information, and to ensure timeliness and accuracy, data collection should be restricted to a minimum of simple, easily obtained, and unambiguous items. Routine reporting of events, periodic censuses relating to persons, and sample surveys all have advantages and limitations. Probably the most useful tools are long-term care registers, as they enable longitudinal studies of patient cohorts. Reliable but confidential means for linking personal records must be found and all records in the system must flow into a central collecting point.

Classification↗
PubMed1992

[Nutritional research in studies of large numbers of people: the need for integrating accuracy and simplicity].

Epidemiological investigations on nutrition and chronic diseases require high reliability, accuracy, low cost and feasibility of the system through which dietary information is collected. Food frequency questionnaire are commonly used in large epidemiological investigations. However, repeated 24 hour recall should be considered to integrate this information. Multiple 24 h recalls in random samples of large cohorts appear to be convenient choice to improve data accuracy. This procedure also allow calibration of dietary information in case of pooling of data from different cohorts. Multiple 24 h recalls can be easily carried out through telephone interviews instead of multiple face-to-face. This reliable procedure, tested in a study reported in this paper, may improve compliance.

Adult↗
PubMed1993

Evaluating the accuracy of transcribed clinical data.

This study evaluated the accuracy of data transcribed into a computer-stored record from a handwritten listing of pediatric immunizations. The immunization records of 459 children seen in the UCLA Children's Health Center in March, 1993 were transcribed into a clinical computer system on an ongoing basis. Of these records, 27 (5.9%) were subsequently found to be inaccurate. Reasons for inaccuracy in the transcribed records included incomplete written records, incomplete transcription of written records, and unavailability of immunization records from multiple health-care providers. The utility of a computer-stored clinical record may be adversely affected by unavoidable inaccuracies in transcribed clinical data.

Child↗
PubMed2005

Challenges in systematic reviews of diagnostic technologies.

Diagnostic tests are critical components of effective health care. They help determine treatments that are most beneficial for a given patient. Their assessment is a complex process that includes such challenges as a dearth of studies that evaluate clinical outcomes and lack of data on use of the test in realistic clinical settings. The methodologic quality of studies of diagnostic tests also lags behind the quality of studies of therapeutic interventions. Statistical methods to combine diagnostic accuracy data are more complex and not as well developed, leading to difficulties in the interpretation of results. The Agency for Healthcare Research and Quality Technology Assessment Program has adopted a 6-level framework for evaluating diagnostic technologies. The model emphasizes the need for systematic reviews of diagnostic test studies to go beyond the assessment of technical feasibility and accuracy to examine the impact of the test on health outcomes. In this paper, we use examples from 3 Evidence-based Practice Center reports to illustrate 3 challenges reviewers may face when reviewing diagnostic test literature: finding relevant studies, assessing methodologic quality of diagnostic accuracy studies, and synthesizing studies that evaluate tests in different patient populations or use different outcomes.

Diagnostic Techniques and Procedures↗
PubMed1985

An evaluation of the accuracy of pharmacokinetic data for the computer assisted infusion of alfentanil.

The accuracy of using average alfentanil pharmacokinetic data in a computer assisted infusion pump (TIAC) to predict alfentanil plasma concentrations was tested in 35 patients (divided into three groups) receiving alfentanil and nitrous oxide in oxygen anaesthesia for lower and upper abdominal surgery. By frequently measuring the arterial plasma concentration, it was possible to determine the average prediction error for individual patients and for groups of patients. For the groups, there were no significant systematic over- or underpredictions of the alfentanil plasma concentrations (bias). However, there existed a moderate degree of variability (imprecision) within the groups, caused by deviations of measured and predicted plasma concentrations in the individual patients within each group. As a result, prediction errors of 22.2-32.5% can be expected with the average pharmacokinetic data used in this study to drive TIAC. It was concluded that, as a result of the moderate degree of imprecision, it is unwise to rely totally on the absolute values of alfentanil plasma concentrations predicted by a computer-regulated infusion pump such as TIAC. However, such devices can be used to attain rapidly a relatively stable plasma concentration that can be adjusted (titrated) to the requirements of an individual patient during anaesthesia.

Adjuvants, Anesthesia↗
PubMed2005

Ab initio and direct quasiclassical-trajectory study of the F+CH4-->HF+CH3 reaction.

We present an electronic structure and dynamics study of the F+CH4-->HF+CH3 reaction. CCSD(T)/aug-cc-pVDZ geometry optimizations, harmonic-frequency, and energy calculations indicate that the potential-energy surface is remarkably isotropic near the transition state. In addition, while the saddle-point F-H-C angle is 180 degrees using MP2 methods, CCSD(T) geometry optimizations predict a bent transition state, with a 153 degrees F-H-C angle. We use these high-quality ab initio data to reparametrize the parameter-model 3 (PM3) semiempirical Hamiltonian so that calculations with the improved Hamiltonian and employing restricted open-shell wave functions agree with the higher accuracy data. Using this specific-reaction-parameter PM3 semiempirical Hamiltonian (SRP-PM3), we investigate the reaction dynamics by propagating quasiclassical trajectories. The results of our calculations using the SRP-PM3 Hamiltonian are compared with experiments and with the estimates of two recently reported potential-energy surfaces. The trajectory calculations using the SRP-PM3 Hamiltonian reproduce quantitatively the measured HF vibrational distributions. The calculations also agree with the experimental HF rotational distributions and capture the essential features of the excitation function. The results of the SRP semiempirical Hamiltonian developed here clearly improve over those using the two prior potential-energy surfaces and suggest that reparametrization of semiempirical Hamiltonians is a promising strategy to develop accurate potential-energy surfaces for reaction dynamics studies of polyatomic systems.

Journal Article↗
PubMedDate not supplied

Prediction of electron beam output factors.

A method to predict square and rectangular field output factors from the measurement of selected fields of electron beams on the Therac 20 Saturne has been developed. A two parameter fit of the square field output factor data, based on the functional dependence as predicted by a pencil beam calculational model, has proven clinically acceptable. The pencil beam distributions are given by the Fermi-Eyges theory of multiple Coulomb scattering. For a rectangular field, the output factor can be calculated from the square root of the product of the two square field output factors wtih sides equal to those of the rectangular field. If however, there is a significant asymmetry between the X and Y collimator systems, then rectangular field output factors should be predicted from the product of the X and Y one-dimensional output factors. One-dimensional output factors are defined as output factors of rectangular fields where one side remains constant and equal to the side of the square reference field. Measured data indicate either of the two methods of determining rectangular field output factors to be clinically acceptable for the Therac 20, the use of one-dimensional output factors demonstrating greater accuracy. Data show agreement to within approximately 1.5% at electron energies of 6, 9, 13, and 17 MeV.

Electrons↗
PubMed2000

Accuracy of hospital discharge data for cancer registration and epidemiological research in Northern Ireland.

BACKGROUND: Cancer registries provide a basis for many epidemiological studies in cancer. Electronic data provide for prompt, economical data capture for disease registries; doubts, however, exist about their data quality. MATERIALS AND METHODS: We examined the accuracy for cancer registration of a subset of 7043 electronically captured hospital discharge data. RESULTS: Note availability was 82%. Of the notes available for examination demographic data accuracy was high; however, 7.4% of cases coded on discharge as cancer had no malignancy recorded in case notes while 4. 1% had in-situ or benign tumors. Almost a third had some inaccuracy in coding tumor site. Prevalent cases accounted for 17.2% of cases examined reflecting a new registry. Electronic data capture reduces time spent examining notes; only 40% of cases notified from PAS required a quick validation check. It enhances data completeness; without electronic discharge data 11.5% of the final database would have been missed. The validation check prevented overinflation of the cancer registration database by 7.5%. Measures of accuracy in the final database were high. CONCLUSION: This study shows that discharge data are a valuable data source for cancer registries but require a targeted note review aimed at cases without corroborating data.

Adult↗
PubMedDate not supplied

Effects of nicotinic dimethylaminoethyl esters on working memory performance of rats in the radial-arm maze.

Nicotine has been found to improve memory performance in a variety of tests, including the radial-arm maze. This improvement, together with the consistent finding of a decline in cortical nicotinic receptor concentration in Alzheimer's patients, has fueled the search for novel nicotinic ligands with therapeutic potential. In the current studies, a series of nicotinic compounds was tested for effects on working memory performance in the radial-arm maze. One of the three compounds tested, DMAE II (dimethylaminoethanol cyclohexyl carboxylate fumurate), produced significant improvements in working memory performance. In the first experiment, this drug produced a biphasic dose-response curve with improved performance at the 20-mg/kg dose but not at 10 or 40 mg/kg. In a second round of DMAE II administration, the same rats showed a significant improvement with the 40-mg/kg dose. In the second experiment, a new set of rats also showed a biphasic dose-response to DMAE II. The 20-mg/kg dose caused a significant improvement whereas the 40-mg/kg dose did not. Interactions of DMAE II with nicotine and mecamylamine were also studied. Nicotine (0.2 mg/kg) by itself caused a significant improvement in working memory performance. No additive effects of DMAE II with nicotine were seen. In fact, some attenuation of response was seen with the combination. Choice accuracy data for mecamylamine could not be analyzed because of excessive sedation and nonresponding. These studies show that, like nicotine, the nicotinic ligand DMAE II causes an improvement in radial-arm mace choice accuracy. The lack of additivity with nicotine may have been to the partial agonist effects of DMAE II.

Animals↗
PubMed1987

Structure and process in semantic memory: new evidence based on speed-accuracy decomposition.

Reaction-time and accuracy data obtained from studies of sentence verification have not been rich enough to answer certain important theoretical questions about structures and processes in human semantic memory. However, a new technique called speed-accuracy decomposition (Meyer, Irwin, Osman, & Kounios, 1986) may help solve this problem. The technique allows intermediate products of sentence verification to be analyzed more precisely. Three experiments with speed-accuracy decomposition indicate that verification processes produce useful partial information before they are completed. Such information appears to accumulate continuously at a rate whose magnitude depends on the degree of relatedness between semantic categories. This outcome is consistent with continuous computational (e.g., semantic-feature comparison) models of semantic memory. An analysis of reaction-time minima suggests that a discrete all-or-none search process may also contribute at least occasionally to sentence verification. Further details regarding the nature of these processes and the memory structures on which they operate can be inferred from additional results obtained through speed-accuracy decomposition.

Humans↗
PubMed2005

The use of an electronic audience response system for data collection.

BACKGROUND: Gathering complete and accurate data from community groups, particularly medically underserved populations, is challenging. METHODS: An electronic audience response system (ARS) is a novel method for the efficient collection of data while maintaining participant confidentiality in group settings. RESULTS: Because data are captured electronically, an ARS eliminates the need to transfer data from paper forms, reducing errors and the amount of time required for data management. CONCLUSIONS: ARS is a useful data collection tool that works well with diverse populations and greatly increases data accuracy and completeness while maintaining participant confidentiality.

Computer Communication Networks↗
PubMed2006

Investigating the accuracy of ethnicity data in New Zealand hospital records: still room for improvement.

BACKGROUND: The accuracy of ethnicity information in the New Zealand hospital data was reported on in 1994. Data collected in the Barriers to Diabetes Care in the Waikato Study enables further evaluation of the accuracy of ethnicity information in hospital records. AIMS: One aim of public health policy is addressing health disparities between ethnic groups. Monitoring disparities depends on accurate outcome data, such as that from hospitals. It would be expected that this data would improve over time. This paper reports on the contemporary accuracy of ethnicity data in hospital records in the Waikato district. METHODS: Self-identified ethnicity data were gathered as part of the Barriers to Diabetes Care in the Waikato mail survey. Hospital record data were collected for those participants who had consented for access to their hospital records. RESULTS: Complete data was available for 3500 people with diabetes. Ethnicity in the hospital record was correct for one of the sometimes multiple, self-identified ethnicities for 97.7 (95CI 96.8-98.3)% of respondents. Ethnicity data were concordant for 71 (67-75)% of Maori and 99 (99-100)% of non-Maori. The non-Maori ethnic group was disaggregated into component groups: the hospital record agreed with self identified ethnicity for 89 (87-91)% of Europeans, 67 (55-78)% of Pacific groups, 70 (57-81)% of South Asian groups, 64 (48-77)% of Asian groups, and 41 (27-57)% of 'Other' ethnic groups. CONCLUSIONS: Hospital records continue to mis-record ethnicity when compared to a self-identified ethnicity. Mis-recording occurs for all ethnic groups, and is more pronounced at more specific levels of ethnic group. Researchers, clinicians, and policy makers must be cognisant of these continuing discrepancies when using hospital record data to describe ethnic variations in health status, service utilisation, or for policy planning activities.

Ethnicity↗
PubMed1978

A scheme for the evaluation of methods in clinical chemistry with particular application to those measuring enzyme activities. Part II: analysis of data and performance assessment.

Recommendations are made concerning the editing of day-to-day reproducibility data for establishment of precision in the evaluation of a clinical chemistry method. The concept of diagnostic and equalized diagnostic indices is introduced together with formulae for their generation from the usual precision and accuracy data acquired in method evaluations. These indices allow direct comparison of data obtained from procedures for measuring enzyme activities which employ a variety of experimental conditions and units in their protocols. The equalized diagnostic index permits assessment of the suitability of the normal range assignment. Permissible limits of variation (PLV) and permissible limits of discrepancy (PLD) have been developed empirically from detailed examination of data from method evaluations and proficiency testing surveys in the published literature. The application of the diagnostic indices and the two permissible limits of criteria have been illustrated using data from the assessment of 19 kits measuring CPK activity. The inconsistency of the correlation coefficient in method comparisons is confirmed.

Canada↗
PubMed1999

A new version of the RDP (Ribosomal Database Project).

The Ribosomal Database Project (RDP-II), previously described by Maidak et al. [ Nucleic Acids Res. (1997), 25, 109-111], is now hosted by the Center for Microbial Ecology at Michigan State University. RDP-II is a curated database that offers ribosomal RNA (rRNA) nucleotide sequence data in aligned and unaligned forms, analysis services, and associated computer programs. During the past two years, data alignments have been updated and now include >9700 small subunit rRNA sequences. The recent development of an ObjectStore database will provide more rapid updating of data, better data accuracy and increased user access. RDP-II includes phylogenetically ordered alignments of rRNA sequences, derived phylogenetic trees, rRNA secondary structure diagrams, and various software programs for handling, analyzing and displaying alignments and trees. The data are available via anonymous ftp (ftp.cme.msu. edu) and WWW (http://www.cme.msu.edu/RDP). The WWW server provides ribosomal probe checking, approximate phylogenetic placement of user-submitted sequences, screening for possible chimeric rRNA sequences, automated alignment, and a suggested placement of an unknown sequence on an existing phylogenetic tree. Additional utilities also exist at RDP-II, including distance matrix, T-RFLP, and a Java-based viewer of the phylogenetic trees that can be used to create subtrees.

Base Sequence↗
PubMed1990

Individual analysis of laterality data.

Graphical and statistical analyses are presented that allow one to check for an individual subject whether the performance during a session is stable, whether the difference between the left and the right visual half-field is significant, and whether the performance is uniform over different sessions. Analyses are given for accuracy data and for latency data. Though the analyses are described for a visual half-field experiment, they can easily be adapted for other laterality tasks.

Attention↗
PubMed1976

A Fourier method for the analysis of exponential decay curves.

A method based on the Fourier convolution theorem is developed for the analysis of data composed of random noise, plus an unknown constant "base line," plus a sum of (or an integral over a continuous spectrum of) exponential decay functions. The Fourier method's usual serious practical limitation of needing high accuracy data over a very wide range is eliminated by the introduction of convergence parameters and a Gaussian taper window. A computer program is described for the analysis of discrete spectra, where the data involves only a sum of exponentials. The program is completely automatic in that the only necessary inputs are the raw data (not necessarily in equal intervals of time); no potentially biased initial guesses concerning either the number or the values of the components are needed. The outputs include the number of components, the amplitudes and time constants together with their estimated errors, and a spectral plot of the solution. The limiting resolving power of the method is studied by analyzing a wide range of simulated two-, three-, and four-component data. The results seem to indicate that the method is applicable over a considerably wider range of conditions than nonlinear least squares or the method of moments.

Computers↗
PubMed1983

Multidimensional influences of cerebral asymmetries on visual half-field asymmetries and cognitive skills.

Evoked potentials to laterally presented stimuli were collected from left and right tempero-parietal sites during performance of two visual half-field tasks, lexical decision, and line orientation discrimination. Reaction time and accuracy data were simultaneously collected. The behavioral data indicated the development of a right field advantage for the lexical decision task as a function of practice. A principal components analysis revealed three independent evoked potential components which displayed task-dependent hemispheric asymmetries. Multiple regression analyses revealed that visual half-field asymmetries in response accuracy were closely related to hemispheric asymmetries on several independent evoked response components. Subject's scores on independent tests of verbal reasoning and spatial relations were also found to be closely related to hemispheric asymmetry on several independent evoked response components. These data support a multidimensional concept of cerebral specialization. They also suggest that visual field asymmetries reflect the confluence of several underlying processes which have independent lateralization distributions across the population. In general, the results underscore the need for further research on the nature of the relationship between cerebral and perceptual asymmetries.

Adolescent↗
PubMed2004

The use of online control: a developmental perspective.

To date very little research has addressed the abilities of young participants to respond to a change in visual information provided during movement execution. This study attempted to determine the ability of 45 participants (5, 7, 9 years) to respond to a change in visual information during a discrete rapid aiming movement. A perturbation paradigm where the target size changed after movement onset was used. In the control context, movements were made to each target size (small, medium, large) with no perturbation. In contrast, during the experimental context the target always began as a medium target. Upon movement initiation, the target size could remain constant or might unexpectedly become larger or smaller. Temporal, kinematic, and correction data were collected to determine the control process underlying the aiming movement. No interaction was found between age and condition for movement time (MT), and results indicated that all ages scaled movement time to final target size. The accuracy data revealed the 9-year-old participants were more accurate than the 5- and 7-year-old participants. To determine where the changes in duration were made, the time to and after peak velocity (TTPV, TAPV), and peak velocity values (PV) were examined. The PV values indicated that, during the control context, the participants scaled their movement to the target size. However, during the experimental condition generally no significant differences were found in either measure, suggesting a programmed response based on the original target size. This was supported by the correction data collected prior to peak velocity, lending further support to a programmed response. Following peak velocity, it was found that differences in MT were as a result of time spent in deceleration. This increased TAPV, and increased number of corrections observed, suggest that all participants were using on-line control following peak velocity in response to the change in visual information. The data collected supports a model of control that incorporates both open-loop control during the initial impulse phase, and closed-loop control during the current control phase for participants as young as 5 years.

Age Factors↗