Texas health officials announced Monday that they are changing the way the state reports a key metric used to evaluate the extent of coronavirus infection, a move that conceded that the state’s previous method of calculating the “positivity rate” muddied the extent of viral transmission by mixing old data with new.
The Texas Department of State Health Services said it will now “primarily rely” on a new calculation of the daily positivity rate — defined as the share of tests that yield positive results — that takes into account the date on which a coronavirus test was administered. Officials said the new metric will give a more accurate representation of viral transmission in Texas on a given day.
It also means that each day’s positivity rate will be an oft-changing number, fluctuating as officials collect lab results over time. Labs and hospitals report their test results to the state with varying degrees of timeliness, and state officials will have to recalculate the positivity rates for previous days as more test results from those dates pour in.
