D.C. Mayor Muriel E. Bowser (D) is expected Wednesday to announce the gradual reopening of the capital, saying the city has been meeting key thresholds to contain new coronavirus infections.

Hospitals have been running below their maximum capacity, testing is on the rise and the city is in the process of hiring enough contact tracers to identify and quarantine residents exposed to the virus.

But the city has been moving the goal posts for measuring the trajectory of the virus.

District officials have changed their approach to calculating the spread of the virus — no longer mentioning other reopening metrics they laid out last month, including a declining rate in people testing positive and a decrease in flu-like illnesses among residents who might not have been tested.

At a Tuesday news conference, the mayor said she understood the challenges in interpreting data relied on by epidemiologists and understanding why each jurisdiction seems to be using drastically different measurement tools to determine when to reopen businesses and resume public gatherings. She urged the public to have confidence in the city’s data.

“I can tell you we have no interest in cooking the books,” Bowser said. “We have put out proactively a lot of information on a daily basis, and we will continue to do that.”

Like other jurisdictions, the District has navigated unfamiliar waters to determine when to safely reopen and how to best communicate the trends to the public. Neighboring Maryland and Virginia have emphasized different benchmarks to reopen their economies.

In April, the mayor and officials in her administration repeatedly said they wanted to see a two-week decline in new cases before reopening the city.

By mid-May, city officials said they were instead looking for a decline in the community spread of the virus — counting new infections by the date people reported developing symptoms, not when they tested positive. The new metric excludes cases at nursing homes, homeless shelters, jails and other confined facilities that are less likely to spread the virus outside their walls.

Experts said that although other jurisdictions are looking for a decline in total infections, including in those facilities, the District’s approach makes sense from a public health perspective. But the community spread metric also has its limitations.

Epidemiology professors William Hanage of Harvard and Jeffrey Klausner of the University of California, Los Angeles both questioned how the District handles the many people who are infected but never develop symptoms — perhaps one-sixth of all cases, Klausner estimated.

The symptom-onset date is also self-reported, meaning it depends on city employees reaching infected patients to interview them. The city has not answered questions about what percentage of known patients have been accounted for in the community-spread count or how it handles asymptomatic cases.

Over the weekend, the District hit a setback in achieving a two-week decline in the virus’s spread after recording a single-day spike in new cases, from 68 on May 12 to 118 on May 13. But instead of resetting the 14-day clock to zero, the District removed the two days that showed that spike, meaning the city could still begin reopening on Friday as the mayor had already floated.

City officials said the spike was not significant enough to throw off the city’s reopening plans. At her news conference Tuesday, Bowser described the two-week decline as a “shorthand” to move to a recovery phase of the pandemic.

“The 14 days are established as a metric to suggest that if there is an increase in the next phase, that all of our systems would be able to accommodate that rise in the next phase,” Bowser said.

White House officials last week raised concerns about the high rate of people testing positive for coronavirus in the D.C. area, calling the capital region the worst in the country by this measure.

To date, about 24 percent of D.C. residents who have been tested for coronavirus have tested positive. The positivity rate has been closer to 15 percent over the last four days.

In an April 29 presentation, District officials originally listed as one of the requirements to begin reopening that the positivity rate fall below 5 percent. But the city has never come close to that benchmark.

On a Sunday call with reporters, D.C. Health director LaQuandra Nesbitt said the city can enter phase one with a positivity rate below 20 percent.

The mayor and her chief of staff repeatedly demurred when asked to explain the change.

“We have been very prudent about our approach to reopening,” said John Falcicchio, the mayor’s chief of staff. “Never has the mayor said we want to reopen despite what the metrics say.”

Bowser said the city has not seen a significant decline in the positivity rate because it has not yet conducted widespread testing for people without symptoms.

Despite conflicting data on the decline of the virus, experts said residents should take comfort that hospitals have been below 80 percent occupancy for more than two weeks. The purpose of “flattening the curve” with social distancing was to give hospitals time to prepare for surges.

“In a rational world, the CDC would put out guidelines for surveillance, and every jurisdiction would follow those surveillance guidelines. We’d have a coordinated federal response,” said Klausner, the UCLA epidemiologist. “But we don’t live in that world. We’re dealing with every jurisdiction doing their own thing.”