The Experts below are selected from a list of 264 Experts worldwide ranked by ideXlab platform
Curtis A Parvin - One of the best experts on this subject based on the ideXlab platform.
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evaluation of the performance of randomized versus fixed time schedules for Quality Control Procedures
Clinical Chemistry, 2007Co-Authors: Curtis A Parvin, Sanford RobbinsAbstract:Background: Although minimum regulatory standards exist for determining QC testing frequency, decisions regarding when and how to run QC samples are not standardized. Most QC testing strategies test Control samples at fixed time intervals, often placing the samples in the same position on an instrument during subsequent QC events and leaving large gaps of time when Control samples are never run, yet patient samples are being tested. Methods: Mathematical derivations and computer simulation were used to determine the expected waiting time between an out-of-Control condition and the next scheduled QC test for various QC testing strategies that use fixed or random intervals between QC tests. Results: Scheduling QC tests at fixed intervals yields an average time between the occurrence of an out-of-Control error condition and the next scheduled QC test that is equal to half of the fixed time interval. This performance was the best among the QC scheduling strategies investigated. Near-optimal performance, however, was achieved by randomly selecting time intervals between QC events centered on the desired expected interval length, a method that provides variation in QC testing times throughout the day. Conclusions: If the goal is to vary QC testing times throughout the day while maintaining the shortest expected length of time between error conditions and the next scheduled QC test, then a near-optimal QC scheduling strategy combines randomly selected time intervals centered on the desired length of time between QC events with fixed time intervals.
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performance evaluation and planning for patient based Quality Control Procedures
American Journal of Clinical Pathology, 2000Co-Authors: Jay J Ye, Stephen C Ingels, Curtis A ParvinAbstract:In a recent publication, the effect of the length of time between the routine testing of Quality-Control (QC) samples on QC performance was studied using a newly proposed performance measure: the average number of patient samples that contain unacceptable analytic error due to an out-of-Control error condition (ANPTE). We show that ANPTE also perfectly suits the evaluation of patient-based QC Procedures. We used ANPTE to study the effect of the number of patient results averaged and the width of the truncation limits on an average of normals QC procedure. Estimates of ANPTE were obtained by using computer simulations that use actual patient result distributions. Based on ANPTE, the conclusions about the effects of truncation limits and number of patient results averaged on the performance of an average of normals QC procedure are substantially different from those described by others using the probability of error detection to characterize QC performance.
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estimating the performance characteristics of Quality Control Procedures when error persists until detection
Clinical Chemistry, 1991Co-Authors: Curtis A ParvinAbstract:The concepts of the power function for a Quality-Control rule, the error detection rate, and the false rejection rate were major advances in evaluating the performance characteristics of Quality-Control Procedures. Most early articles published in this area evaluated the performance characteristics of Quality-Control rules with the assumption that an intermittent error condition occurred only within the current run, as opposed to a persistent error that continued until detection. Difficulties occur when current simulation methods are applied to the persistent error case. Here, I examine these difficulties and propose an alternative method that handles persistent error conditions effectively when evaluating and quantifying the performance characteristics of a Quality-Control rule.
Thomas N Robinson - One of the best experts on this subject based on the ideXlab platform.
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evaluation of Quality Control Procedures for 24 h dietary recalls results from the girls health enrichment multisite studies
Preventive Medicine, 2004Co-Authors: Karen W Cullen, Kathy Watson, John H Himes, Tom Baranowski, James Rochon, Myron Waclawiw, Mary Stevens, Deborah Leachman Slawson, Donna Matheson, Thomas N RobinsonAbstract:Abstract Background . Quality Control methods are key components of dietary assessment, but have rarely been evaluated. Methods . One hundred forty-four 8–10-year-old African-American girls at three field centers completed two 24-h dietary recalls at baseline before a pilot weight gain prevention intervention (one recall collected in-person and one by telephone). The dietary recall data were initially reviewed by the dietary interviewer (Phase 1), then by a local lead nutritionist at the field center (Phase 2), and then by the Nutrition Coordinating Center (NCC) (Phase 3); any differences identified by NCC were reconciled (Phase 4). Bland–Altman and generalizability theory methods were used to assess agreement of consumption for selected food variables and nutrients between phases. Results . Only small differences occurred. Quality Control Procedures primarily reduced the variances of nutrients rather than caused the means to shift. Most of the variability among phases was due to individual level variability in dietary intake. Conclusions . Decisions to review dietary recall data beyond local review should be based on the level of precision and accuracy required for the study outcomes and the availability of financial resources.
Karen W Cullen - One of the best experts on this subject based on the ideXlab platform.
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Evaluation of Quality Control Procedures for 24-h dietary recalls: results from the Girls Health Enrichment Multisite Studies.
Preventive medicine, 2020Co-Authors: Karen W Cullen, Kathy Watson, John H Himes, Tom Baranowski, James Rochon, Myron Waclawiw, Mary Stevens, Deborah Leachman Slawson, Donna MathesonAbstract:Quality Control methods are key components of dietary assessment, but have rarely been evaluated. One hundred forty-four 8-10-year-old African-American girls at three field centers completed two 24-h dietary recalls at baseline before a pilot weight gain prevention intervention (one recall collected in-person and one by telephone). The dietary recall data were initially reviewed by the dietary interviewer (Phase 1), then by a local lead nutritionist at the field center (Phase 2), and then by the Nutrition Coordinating Center (NCC) (Phase 3); any differences identified by NCC were reconciled (Phase 4). Bland-Altman and generalizability theory methods were used to assess agreement of consumption for selected food variables and nutrients between phases. Only small differences occurred. Quality Control Procedures primarily reduced the variances of nutrients rather than caused the means to shift. Most of the variability among phases was due to individual level variability in dietary intake. Decisions to review dietary recall data beyond local review should be based on the level of precision and accuracy required for the study outcomes and the availability of financial resources.
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evaluation of Quality Control Procedures for 24 h dietary recalls results from the girls health enrichment multisite studies
Preventive Medicine, 2004Co-Authors: Karen W Cullen, Kathy Watson, John H Himes, Tom Baranowski, James Rochon, Myron Waclawiw, Mary Stevens, Deborah Leachman Slawson, Donna Matheson, Thomas N RobinsonAbstract:Abstract Background . Quality Control methods are key components of dietary assessment, but have rarely been evaluated. Methods . One hundred forty-four 8–10-year-old African-American girls at three field centers completed two 24-h dietary recalls at baseline before a pilot weight gain prevention intervention (one recall collected in-person and one by telephone). The dietary recall data were initially reviewed by the dietary interviewer (Phase 1), then by a local lead nutritionist at the field center (Phase 2), and then by the Nutrition Coordinating Center (NCC) (Phase 3); any differences identified by NCC were reconciled (Phase 4). Bland–Altman and generalizability theory methods were used to assess agreement of consumption for selected food variables and nutrients between phases. Results . Only small differences occurred. Quality Control Procedures primarily reduced the variances of nutrients rather than caused the means to shift. Most of the variability among phases was due to individual level variability in dietary intake. Conclusions . Decisions to review dietary recall data beyond local review should be based on the level of precision and accuracy required for the study outcomes and the availability of financial resources.
Donna Matheson - One of the best experts on this subject based on the ideXlab platform.
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Evaluation of Quality Control Procedures for 24-h dietary recalls: results from the Girls Health Enrichment Multisite Studies.
Preventive medicine, 2020Co-Authors: Karen W Cullen, Kathy Watson, John H Himes, Tom Baranowski, James Rochon, Myron Waclawiw, Mary Stevens, Deborah Leachman Slawson, Donna MathesonAbstract:Quality Control methods are key components of dietary assessment, but have rarely been evaluated. One hundred forty-four 8-10-year-old African-American girls at three field centers completed two 24-h dietary recalls at baseline before a pilot weight gain prevention intervention (one recall collected in-person and one by telephone). The dietary recall data were initially reviewed by the dietary interviewer (Phase 1), then by a local lead nutritionist at the field center (Phase 2), and then by the Nutrition Coordinating Center (NCC) (Phase 3); any differences identified by NCC were reconciled (Phase 4). Bland-Altman and generalizability theory methods were used to assess agreement of consumption for selected food variables and nutrients between phases. Only small differences occurred. Quality Control Procedures primarily reduced the variances of nutrients rather than caused the means to shift. Most of the variability among phases was due to individual level variability in dietary intake. Decisions to review dietary recall data beyond local review should be based on the level of precision and accuracy required for the study outcomes and the availability of financial resources.
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evaluation of Quality Control Procedures for 24 h dietary recalls results from the girls health enrichment multisite studies
Preventive Medicine, 2004Co-Authors: Karen W Cullen, Kathy Watson, John H Himes, Tom Baranowski, James Rochon, Myron Waclawiw, Mary Stevens, Deborah Leachman Slawson, Donna Matheson, Thomas N RobinsonAbstract:Abstract Background . Quality Control methods are key components of dietary assessment, but have rarely been evaluated. Methods . One hundred forty-four 8–10-year-old African-American girls at three field centers completed two 24-h dietary recalls at baseline before a pilot weight gain prevention intervention (one recall collected in-person and one by telephone). The dietary recall data were initially reviewed by the dietary interviewer (Phase 1), then by a local lead nutritionist at the field center (Phase 2), and then by the Nutrition Coordinating Center (NCC) (Phase 3); any differences identified by NCC were reconciled (Phase 4). Bland–Altman and generalizability theory methods were used to assess agreement of consumption for selected food variables and nutrients between phases. Results . Only small differences occurred. Quality Control Procedures primarily reduced the variances of nutrients rather than caused the means to shift. Most of the variability among phases was due to individual level variability in dietary intake. Conclusions . Decisions to review dietary recall data beyond local review should be based on the level of precision and accuracy required for the study outcomes and the availability of financial resources.
Myron Waclawiw - One of the best experts on this subject based on the ideXlab platform.
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Evaluation of Quality Control Procedures for 24-h dietary recalls: results from the Girls Health Enrichment Multisite Studies.
Preventive medicine, 2020Co-Authors: Karen W Cullen, Kathy Watson, John H Himes, Tom Baranowski, James Rochon, Myron Waclawiw, Mary Stevens, Deborah Leachman Slawson, Donna MathesonAbstract:Quality Control methods are key components of dietary assessment, but have rarely been evaluated. One hundred forty-four 8-10-year-old African-American girls at three field centers completed two 24-h dietary recalls at baseline before a pilot weight gain prevention intervention (one recall collected in-person and one by telephone). The dietary recall data were initially reviewed by the dietary interviewer (Phase 1), then by a local lead nutritionist at the field center (Phase 2), and then by the Nutrition Coordinating Center (NCC) (Phase 3); any differences identified by NCC were reconciled (Phase 4). Bland-Altman and generalizability theory methods were used to assess agreement of consumption for selected food variables and nutrients between phases. Only small differences occurred. Quality Control Procedures primarily reduced the variances of nutrients rather than caused the means to shift. Most of the variability among phases was due to individual level variability in dietary intake. Decisions to review dietary recall data beyond local review should be based on the level of precision and accuracy required for the study outcomes and the availability of financial resources.
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evaluation of Quality Control Procedures for 24 h dietary recalls results from the girls health enrichment multisite studies
Preventive Medicine, 2004Co-Authors: Karen W Cullen, Kathy Watson, John H Himes, Tom Baranowski, James Rochon, Myron Waclawiw, Mary Stevens, Deborah Leachman Slawson, Donna Matheson, Thomas N RobinsonAbstract:Abstract Background . Quality Control methods are key components of dietary assessment, but have rarely been evaluated. Methods . One hundred forty-four 8–10-year-old African-American girls at three field centers completed two 24-h dietary recalls at baseline before a pilot weight gain prevention intervention (one recall collected in-person and one by telephone). The dietary recall data were initially reviewed by the dietary interviewer (Phase 1), then by a local lead nutritionist at the field center (Phase 2), and then by the Nutrition Coordinating Center (NCC) (Phase 3); any differences identified by NCC were reconciled (Phase 4). Bland–Altman and generalizability theory methods were used to assess agreement of consumption for selected food variables and nutrients between phases. Results . Only small differences occurred. Quality Control Procedures primarily reduced the variances of nutrients rather than caused the means to shift. Most of the variability among phases was due to individual level variability in dietary intake. Conclusions . Decisions to review dietary recall data beyond local review should be based on the level of precision and accuracy required for the study outcomes and the availability of financial resources.
