What is the Difference Between Precision and Accuracy in Airborne Mold Spore Counts?
Some people are confused about the difference between precision and accuracy. An airborne mold spore count obtained from a spore trap or similar air sampling device can be processed in an aerobiology lab or mold test lab by several methods of varying accuracy depending on not only the site variables (which dominate the airborne particle count, but also depending on the skill and experience of the lab technician, the quality of the microscope and slide preparation, and the percentage of the particle trace that is examined. In the hands of a skilled microscopist who uses the best practices and who examines 100% of the particle trace, the resulting lab report can give mold spore count that is very precise – for example, citing 5,731 Aspergillus niger spores per M3 (cubic meter) of air. But what the mold test field investigator and laboratory technician may not be able to report is that the variability from minute to minute in the airborne particle level was enormous, easily by a factor of