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Calibration vs. Validation: Definitions, Best Practices, and Options in the Field
ANDREA J. TIWARI, Sebastian Schmitt, Torsten Tritscher, Juergen Spielvogel, Axel Zerrath, TSI Incorporated
Abstract Number: 179
Working Group: Aerosol Standards
Abstract
As with any scientific or technical effort, data accuracy is important for researchers and others measuring aerosols. Terms like ‘calibration’ and ‘validation’ can be used in reference to judging instrument performance, but standard definitions for these are likely not uniformly accepted within the aerosol community. While the historical definition of ‘calibration’ has simply meant comparing two instruments to each other, in practice most people expect a ‘calibration’ to include any necessary adjustments to have been performed in order to ensure instrument performance (and thus data accuracy). Other terms like ‘validation’, ‘verification’ (and even potentially ‘sanity check’) may offer less in the way of quantitative criteria and ability to rectify any problems discovered, but these terms do not have widely-accepted definitions. This presentation proposes definitions for these terms from an aerosol instrumentation and service provider perspective.
Aerosol measurement-related applications vary widely, as do the approaches that users take to instrument performance and data accuracy. These approaches are informed in part by how desirable on-site instrument validation is for the application. In the interest of quality assurance, the European standardization committee (CEN) is introducing some standardization pertaining to ensuring instrument performance and accuracy (i.e. harmonization). We describe this range of quality-assurance approaches and applications, in order to illustrate the diversity of instrument validation needs within this community.
Performing certain checks and simple tests on a routine basis contributes significantly to ensuring proper instrument performance. This presentation will formalize some recommended routine checks (best practices) for ensuring particle measurement performance with a focus on Condensation Particle Counter (CPC) and Scanning Mobility Particle Sizer (SMPS), and will discuss other options users can consider using onsite within this ‘calibration / validation’ space.