A method for estimation of bias and variability of continuous gas monitor data: application to carbon monoxide monitor accuracy.
A method is presented for the evaluation of the bias, variability, and accuracy of gas monitors. This method is based on using the parameters for the fitted response curves of the monitors. Thereby, variability between calibrations, between dates within each calibration period, and between different units can be evaluated at several different standard concentrations. By combining variability information with bias information, accuracy can be assessed. An example using carbon monoxide monitor data is provided. Although the most general statistical software required for these tasks is not available on a spreadsheet, when the same number of dates in a calibration period are evaluated for each monitor unit, the calculations can be done on a spreadsheet. An example of such calculations, together with the formulas needed for their implementation, is provided. In addition, the methods can be extended by use of appropriate statistical models and software to evaluate monitor trends within calibration periods, as well as consider the effects of other variables, such as humidity and temperature, on monitor variability and bias.
Shulman
Stanley A
SA
National Institute for Occupational Safety and Health, Division of Applied Research and Technology, 4676 Columbia Parkway-R3, Cincinnati, OH 45226, USA.
Smith
Jerome P
JP
D015982:Bias; D002138:Calibration; D002248:Carbon Monoxide / Q000032:analysis*; D002249:Carbon Monoxide Poisoning / Q000517:prevention & control*; D004784:Environmental Monitoring / Q000295:instrumentation / Q000379:methods*; D006801:Humans; D015233:Models, Statistical; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D002248:Carbon Monoxide