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P58 Cluster sampling to estimate key entry error rates
451
Abstracts
other studys' usage. The VSR is also a vehicle to communicate system updates, bug fixes, new features, new developments in the computing industry, and new software to the user community. To relieve the tedium of so many numbers, comic relief is provided on the back page showing that systems people do have a sense of humor. The report also serves as a quick reference when informarion is requested for grants renewals or internal reports. The VSR provides a mechanism to distribute information regarding a study's use of system and data management resources which contributes to the efficient use of these resources.
!'57 BMDPLOT: PUBLICATION-QUALITY SURVIVAL PLOTS FROM BMDP OUTPUT S. Corley and K. Davis
University of Washington Seattle, Washington The BMDPLOT program produces publicarion-quality survival plots from line-printer out-put generated by BMDP survival analysis programs 1L and 2L on VAX VMS computers. The plots may be printed on any PostScript-type laser printer or on an HP 7550 pen plotter. The program is written in VAX FORTRAN with calls to the GKS (Graphical Kernel System) run-rime library of graphics functions. The computer on which the program is to be run must be equipped with GKS. BMDP program 1L estimates a survivor function (i.e., survival curse) using either of two methods-actuarial life table or product-limit. BMDP program 2L performs survival analysis with covariates. BMDPLOT can produce five types of plots depending on the BMDP program 1L using the life table method, one type (cumulative survival) for BMDP program 1L using the product-limit method, and two types (Cox-Snell residual and cumulative hazard) for BMDP program 2L. BMDPLOT can process up to 99 problems (or subproblems) per BMDP job and up to six gr.oups and six strata per problem or sub-problem. BMDPLOT allows the user to specify various plot characteristics (such as plot rifle, axis labels, and axis lengths) or to accept the default characteristics determined by the program.
P58 CLUSTER SAMPLING TO ESTIMATE KEY ENTRY ERROR RATES Lesly A. Pearce
Statistics and Epidemiology Research Corporation Seattle, Washington Quality control in a clinical trial includes estimating the key entry error rate. The number of fields on a form, the number of expected records in the database, and also the error rate are dependent on the form type. We sampled 249 forms (5.2%) containing 9815 fields (3.8%) entered in a distributed data ...... entry__system_as _partof _qualitycontrol in the initial _Phaseof the Stroke Prevention in Atrial Fibrillation (SPAF) study. Individual forms, or clusters of fields, were sampled randomly from within each stratum, or form type. Some or all forms of a given form type were sampled. Unbiased estimates of the error rate and variance were then computed using cluster sampling techniques within a stratum, weighting and summing stratum estimates to then compute the overall rate and variance. Estimation by strict random sampling would have required a fewer number of fields to be sampled (2.3 %), however, a much larger number of forms (approaching 100%) would have been solicited from the clinical sites. While simple random sampling does provide a basis for determining the number of forms necessary to sample within a stratum, cluster sampling is clearly a more efficient method for estimating the error rate and its variance.
i'59 A QUALITY ASSURANCE PROGRAM IN CANCER CLINICAL TRIALS
Joyce Niland, Tamara Odom-Maryon and Christine Blevins
City of Hope National Medical Center Duarte, California
The City of Hope Department of Biostaristics provides data management support for 200 cancer clinical trials. A Quality Assurance (QA) program has been implemented to monitor investigator compliance to protocols, and the quality of data collection. The Protocol Compliance Committee
Abstracts
other studys' usage. The VSR is also a vehicle to communicate system updates, bug fixes, new features, new developments in the computing industry, and new software to the user community. To relieve the tedium of so many numbers, comic relief is provided on the back page showing that systems people do have a sense of humor. The report also serves as a quick reference when informarion is requested for grants renewals or internal reports. The VSR provides a mechanism to distribute information regarding a study's use of system and data management resources which contributes to the efficient use of these resources.
!'57 BMDPLOT: PUBLICATION-QUALITY SURVIVAL PLOTS FROM BMDP OUTPUT S. Corley and K. Davis
University of Washington Seattle, Washington The BMDPLOT program produces publicarion-quality survival plots from line-printer out-put generated by BMDP survival analysis programs 1L and 2L on VAX VMS computers. The plots may be printed on any PostScript-type laser printer or on an HP 7550 pen plotter. The program is written in VAX FORTRAN with calls to the GKS (Graphical Kernel System) run-rime library of graphics functions. The computer on which the program is to be run must be equipped with GKS. BMDP program 1L estimates a survivor function (i.e., survival curse) using either of two methods-actuarial life table or product-limit. BMDP program 2L performs survival analysis with covariates. BMDPLOT can produce five types of plots depending on the BMDP program 1L using the life table method, one type (cumulative survival) for BMDP program 1L using the product-limit method, and two types (Cox-Snell residual and cumulative hazard) for BMDP program 2L. BMDPLOT can process up to 99 problems (or subproblems) per BMDP job and up to six gr.oups and six strata per problem or sub-problem. BMDPLOT allows the user to specify various plot characteristics (such as plot rifle, axis labels, and axis lengths) or to accept the default characteristics determined by the program.
P58 CLUSTER SAMPLING TO ESTIMATE KEY ENTRY ERROR RATES Lesly A. Pearce
Statistics and Epidemiology Research Corporation Seattle, Washington Quality control in a clinical trial includes estimating the key entry error rate. The number of fields on a form, the number of expected records in the database, and also the error rate are dependent on the form type. We sampled 249 forms (5.2%) containing 9815 fields (3.8%) entered in a distributed data ...... entry__system_as _partof _qualitycontrol in the initial _Phaseof the Stroke Prevention in Atrial Fibrillation (SPAF) study. Individual forms, or clusters of fields, were sampled randomly from within each stratum, or form type. Some or all forms of a given form type were sampled. Unbiased estimates of the error rate and variance were then computed using cluster sampling techniques within a stratum, weighting and summing stratum estimates to then compute the overall rate and variance. Estimation by strict random sampling would have required a fewer number of fields to be sampled (2.3 %), however, a much larger number of forms (approaching 100%) would have been solicited from the clinical sites. While simple random sampling does provide a basis for determining the number of forms necessary to sample within a stratum, cluster sampling is clearly a more efficient method for estimating the error rate and its variance.
i'59 A QUALITY ASSURANCE PROGRAM IN CANCER CLINICAL TRIALS
Joyce Niland, Tamara Odom-Maryon and Christine Blevins
City of Hope National Medical Center Duarte, California
The City of Hope Department of Biostaristics provides data management support for 200 cancer clinical trials. A Quality Assurance (QA) program has been implemented to monitor investigator compliance to protocols, and the quality of data collection. The Protocol Compliance Committee