Gov. Phil Murphy is pushing back against criticism of the way the state tallies new cases of COVID-19.

The New Jersey Department of Health says that new cases of the virus the governor reports at his briefings are PCR test results from the last 24 hours. But were all of those people recently infected with the virus? The answer is complicated.

“Find another state in this union that is more transparent with data as it relates to COVID-19. Find another state. I’m completely confident in the data we report,” Murphy said.

The Murphy administration says virtually all the daily reported new cases are positive test results received by the Department of Health within the last 24 hours. But new tests don’t always mean new infections.

“What happens is there's a little bit of a lag between the number of reports we get on a given day,” says Dr. Christina Tan.

In a statement last week, the Department of Health said, "The cases we report every day are 'new' in that the department was just notified of them within the past 24 hours. It is also correct that investigation may have subsequently determined that they were 'old' in that symptoms may have begun long before test result was received."

When asked about that statement at his Monday press briefing, Murphy said, “I'm not saying you were being political, but the genesis of it is, without question, political. It is a conspiracy theory and you know this, which is claiming that for whatever reason we're making this look worse than it is.”

“I think he's doing the best he can with what knowledge he has. From the data. And I think the data aren't perfect,” says Dr. Perry Halkitis.

Halkitis is dean of the Rutgers School of Public Health. He worked with the Murphy administration to develop the state's contact tracing corps.

“PCR testing results are not necessarily reported in a real-time basis. So as a result of that, people could have been sick weeks ago,” he says.

The Centers for Disease Control and Prevention says people who were sick with COVID-19 can have detectable levels of the virus in them for three months, and that's why the Department of Health maintains the epi-curve graph.

If a contact tracer interviews someone who says they were sick weeks or months ago, that information is placed on the epi-curse no by the test date, but by the day the person first felt sick.

“Usually for epidemic curves we look at illness onset over time. So, that's why when we actually do our epidemic curve on the website, it's a little bit different than what we hear on a day-to-day basis from the number of reports,” says Tan.

“How accurate it is? I don't think point in times are as accurate as trends are accurate. So, looking at the trend over time is much more important than looking at one point in time,” says Halkitis.

Cases from other states can also be referred back to New Jersey after contact tracing. The Pennsylvania Department of Health said Monday that out of 200,000 close contacts they've traced since October 2020, just 59 of those were identified as New Jersey residents.

The New York state Department of Health says less than 2% of its total cases are from out-of-state residents.