The vast majority of tests being done in our population are negative. As disease reduction strategies are implemented, the number of positive tests will go down. This assumes that a broad segment of the population is being tested. Early on in March, when testing was much more limited, tests were being done on mostly hospitalized or Emergency Department patients. This limited testing skewed the percent positive higher and showed that this metric needs to have a broad scope of the population being tested to be of maximum utility. In addition, as areas of the country and world have been successful in reducing disease presence, the percent positive tests have steadily declined below 5% sometimes to below 1%. At such low levels, activities are able to return to a more normal pre COVID state. Levels above 10% tend to suggest that not enough testing is being done to adequately track disease presence in a community. Levels between 5-10% can indicate ongoing disease spread with an upward trend being worrisome and downward trend suggesting success at disease reduction. 

The Medical Advisory Board discussed the use of Percent Positive testing as a secondary metric of lower priority than the case rate/100,000 over 14 days. This percent positive metric in the 5-10% range can be used in conjunction with an assessment of a local community risk tolerance as far as influencing the continuum of instruction.